From 6d49222de83b3c181d8787edf7aa253bf7e39024 Mon Sep 17 00:00:00 2001 From: dailz Date: Sun, 5 Apr 2026 23:35:00 +0800 Subject: [PATCH] =?UTF-8?q?feat:=20Phase=201=20MVP=20with=20audit=20fixes?= =?UTF-8?q?=20=E2=80=94=20Wayland=20screen=20capture=20+=20VAAPI=20encodin?= =?UTF-8?q?g?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Phase 1 MVP implementation of wl-webrtc: Wayland screen capture tool with hardware-accelerated VAAPI H.264 encoding and WebTransport output. Includes all 9 runtime bug fixes from code audit (fix-audit-issues plan): CRITICAL: - C2: h264_metadata BSF with repeat_sps/repeat_pps in encode pipeline - C4: FpsLimit wired as timing gate in on_copy_complete HIGH: - C3+A2: DRM device discovery via dmabuf feedback MainDevice event, unified resolve_drm_path() helper (CLI > compositor > auto > fallback) - H2: Separate physical_size (mm) from mode_size (pixels) in wl_output - H1+A3: Multi-output warning + named-output-not-found error MEDIUM: - M5: tv_sec u32->u64 to avoid Y2106 timestamp truncation - M4: Guard against SHM Buffer event (DMA-BUF only) Key components: - src/avhw.rs: FFmpeg VAAPI encoder + filter graph + BSF pipeline - src/state.rs: Wayland event loop + output negotiation + screencopy - src/cap_wlr_screencopy.rs: wlr-screencopy capture source - src/fps_limit.rs: Frame rate limiting with configurable target - src/transform.rs: Frame format conversion utilities --- .gitignore | 19 + Cargo.lock | 873 ++++++ Cargo.toml | 21 + README.md | 56 + analysis.md | 443 +++ build.rs | 1 + .../plans/2026-04-03-wl-webrtc-phase1.md | 2518 +++++++++++++++++ ...026-04-03-wl-webrtc-architecture-design.md | 619 ++++ shell.nix | 18 + src/args.rs | 45 + src/avhw.rs | 672 +++++ src/cap_wlr_screencopy.rs | 64 + src/fps_limit.rs | 77 + src/main.rs | 148 + src/state.rs | 996 +++++++ src/transform.rs | 291 ++ tests/integration_test.rs | 103 + 17 files changed, 6964 insertions(+) create mode 100644 .gitignore create mode 100644 Cargo.lock create mode 100644 Cargo.toml create mode 100644 README.md create mode 100644 analysis.md create mode 100644 build.rs create mode 100644 docs/superpowers/plans/2026-04-03-wl-webrtc-phase1.md create mode 100644 docs/superpowers/specs/2026-04-03-wl-webrtc-architecture-design.md create mode 100644 shell.nix create mode 100644 src/args.rs create mode 100644 src/avhw.rs create mode 100644 src/cap_wlr_screencopy.rs create mode 100644 src/fps_limit.rs create mode 100644 src/main.rs create mode 100644 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features = ["client"] } +ffmpeg-next = "8" +mio = { version = "1.0", features = ["os-poll", "os-ext"] } +signal-hook = "0.3" +signal-hook-mio = { version = "0.2", features = ["support-v1_0"] } +clap = { version = "4", features = ["derive"] } +tracing = "0.1" +tracing-subscriber = "0.3" +anyhow = "1" +drm = "0.12" +drm-fourcc = "2" +libc = "0.2" diff --git a/README.md b/README.md new file mode 100644 index 0000000..030f3b1 --- /dev/null +++ b/README.md @@ -0,0 +1,56 @@ +# wl-webrtc + +Wayland screen capture and encoding tool. + +## Prerequisites + +- **Rust toolchain** (1.70+): `rustup default stable` +- **FFmpeg 6.0+** dev libraries with VAAPI support: + - Arch: `pacman -S ffmpeg` + - Ubuntu/Debian: `apt install libavcodec-dev libavformat-dev libavutil-dev libswscale-dev libva-dev` + - Fedora: `dnf install ffmpeg-devel libva-devel` +- **Wayland** dev libraries: + - Arch: `pacman -S wayland-protocols` + - Ubuntu/Debian: `apt install libwayland-dev wayland-protocols` + - Fedora: `dnf install wayland-devel wayland-protocols-devel` +- **DRM** dev libraries: + - Arch: `pacman -S libdrm` + - Ubuntu/Debian: `apt install libdrm-dev` + - Fedora: `dnf install libdrm-devel` + +## Build + +```bash +cargo build --release +``` + +## Run + +```bash +# Basic capture to file +wl-webrtc --output output.mp4 + +# With custom FPS and bitrate +wl-webrtc --output output.mp4 --fps 60 --bitrate 8000000 + +# Specify DRM device for hardware encoding +wl-webrtc --output output.mp4 --drm-device /dev/dri/renderD128 + +# Verbose mode +wl-webrtc --output output.mp4 -v +``` + +## CLI Arguments + +| Argument | Default | Description | +|---|---|---| +| `-o`, `--output` | (required) | Output file path (e.g., output.mp4) | +| `--output-name` | auto | Wayland output name to capture | +| `--fps` | 30 | Target frames per second | +| `--codec` | h264 | Video codec (h264 only for MVP) | +| `--hw-accel` | vaapi | Hardware acceleration method | +| `--drm-device` | auto | DRM render device path | +| `--bitrate` | auto | Target bitrate in bps | +| `--gop-size` | auto | Group of Pictures size | +| `-v`, `--verbose` | false | Enable verbose logging | +| `--port` | 0 | WebTransport server port (unused in MVP) | diff --git a/analysis.md b/analysis.md new file mode 100644 index 0000000..5f45970 --- /dev/null +++ b/analysis.md @@ -0,0 +1,443 @@ +# wl-screenrec 源码分析 + +## 1. 项目概述 + +wl-screenrec 是一个高性能 Wayland 屏幕录制器，核心特性：原始视频数据不经过 CPU，全程在 GPU 上完成捕获、格式转换和编码。 + +**技术栈**：Rust + FFmpeg（硬件加速）+ Wayland 协议（wayland-client crate）+ mio 事件循环 + +**9 个源文件**： + +| 文件 | 行数 | 职责 | +|------|------|------| +| `main.rs` | ~2430 | 状态机、事件循环、编码管线编排 | +| `avhw.rs` | ~444 | FFmpeg 硬件设备/帧上下文（VAAPI/Vulkan） | +| `audio.rs` | ~405 | 音频捕获→解码→重采样→编码（独立线程） | +| `cap_ext_image_copy.rs` | ~237 | ext-image-copy-capture 协议后端 | +| `filter.rs` | ~194 | FFmpeg 视频滤镜图（crop+scale+transpose） | +| `transform.rs` | ~215 | 坐标系变换（处理旋转/翻转） | +| `cap_wlr_screencopy.rs` | ~165 | wlr-screencopy 协议后端 | +| `fps_limit.rs` | ~130 | 帧率限制器（VRR 感知） | +| `fifo.rs` | ~60 | FFmpeg AVAudioFifo 安全封装 | + +--- + +## 2. 架构概览 + +### 2.1 模块依赖 + +``` + ┌──────────────────────────────┐ + │ main.rs │ + └──┬──┬──┬──┬──┬──┬──┬─────────┘ + │ │ │ │ │ │ │ + ┌───────────┘ │ │ │ │ │ └──────────┐ + ▼ ▼ │ ▼ │ ▼ ▼ + ┌──────────┐ ┌────────┐│┌───────┐ ┌────────┐ ┌──────────┐ + │ avhw.rs │ │filter.rs│││audio.rs│ │fps_limit│ │transform │ + └──────────┘ └───┬────┘│└───┬───┘ └────────┘ └──────────┘ + │ │ │ + ┌───────┤ │ ▼ + ▼ ▼ │ ┌──────┐ + ┌────────────┐┌─────┴┐│fifo.rs│ + │cap_wlr_ ││cap_ │└──────┘ + │screencopy ││ext_* │ + └────────────┘└──────┘ +``` + +**依赖层次**：`fifo/fps_limit/transform`（叶节点）→ `avhw/audio` → `filter` → `cap_*` → `main.rs`（核心）。main.rs 与 cap_*.rs 之间存在**双向依赖**：main 定义 `CaptureSource` trait 和 `State`，cap_* 为 `State` 实现 `Dispatch`。 + +### 2.2 State\ 全局状态 + +核心状态结构体持有以下关键字段： + +- **in_flight_surface**：帧在途状态，跟踪当前帧的捕获生命周期 +- **dma**：DMA-BUF 协议对象，用于 GPU 缓冲区共享 +- **enc**：编码器构造状态机（`EncConstructionStage`），管理从探测到就绪的全过程 +- **starting_timestamp**：首帧时间戳（纳秒），用于音视频同步 +- **args**：命令行参数 +- **errored**：致命错误标志 +- **gm**：Wayland 全局对象列表 +- **xdg_output_manager**：输出几何信息管理器 + +泛型 `S: CaptureSource` 使同一个 State 支持两种截屏后端，无需运行时动态分发。 + +### 2.3 CaptureSource Trait + +定义了屏幕捕获后端的统一接口契约： + +- **关联类型 Frame**：每种后端有自己的帧类型 +- **new()**：从 Wayland 全局对象和输出创建后端实例 +- **alloc_frame()**：分配捕获帧，返回 `Option` 统一同步/异步两种模式 +- **queue_copy()**：提交 DMA-BUF 缓冲区给合成器，请求捕获 +- **on_done_with_frame()**：帧使用完毕后的回收回调 + +| 实现者 | 协议 | 文件 | +|--------|------|------| +| `CapWlrScreencopy` | zwlr-screencopy-unstable-v1 | `cap_wlr_screencopy.rs` | +| `CapExtImageCopy` | ext-image-copy-capture-v1 | `cap_ext_image_copy.rs` | + +关键差异：wlr-screencopy 的 `alloc_frame()` 返回 `None`（异步），ext-image-copy 直接返回 `Some(frame)`（同步）。 + +### 2.4 事件循环 + +采用 mio polling + Wayland 事件队列 + Unix 信号三合一架构： + +- **Token(0)** = 信号（SIGINT/SIGTERM/SIGHUP 退出，SIGUSR1 触发 history flush） +- **Token(1)** = Wayland 连接 fd → `queue.dispatch_pending(&mut state)` +- 超时由 FPS 报告周期驱动 +- 退出时仅 `Complete` 状态才 flush 编码器 + +后端自动选择：探测全局列表，优先 ext-image-copy-capture（跨桌面标准），否则回退 wlr-screencopy。 + +--- + +## 3. Wayland 协议交互层 + +### 3.1 两个后端的事件流对比 + +**wlr-screencopy**： + +``` +capture_output() [异步] + → LinuxDmabuf { format, w, h } × N → 收集格式（仅 LINEAR） + → BufferDone → negotiate_format() + on_frame_allocd() +queue_copy(WlBuffer) + → Ready { timestamp } → on_copy_complete() +``` + +**ext-image-copy-capture**： + +``` +[会话初始化] + → BufferSize / DmabufDevice / DmabufFormat × N → 收集约束 + → Done → negotiate_format() +[每帧] +create_frame() [同步，直接返回 Some] +queue_copy(WlBuffer) + → PresentationTime { timestamp } → 暂存 + → Ready → on_copy_complete() +``` + +核心差异：wlr 每帧触发格式协商（帧级别），ext 在会话建立时完成（会话级别）。ext 提供真实 modifier 列表，wlr 硬编码 `DrmModifier::LINEAR`。 + +### 3.2 DMA-BUF 缓冲区创建 + +零拷贝路径： + +``` +AV HW Surface → av_hwframe_map → DRM PRIME 描述符 (DMA-BUF fd) + → zwp_linux_dmabuf.create_params → add(planes) → create_immed → WlBuffer + → cap.queue_copy(WlBuffer) + → 合成器直接写入 GPU Surface（零拷贝） +``` + +### 3.3 格式协商 + +格式优先级：`XRGB8888` > `XBGR8888` > `XRGB2101010`。VAAPI 模式仅接受 LINEAR modifier，Vulkan 模式接受任意 modifier。 + +DRM 设备发现：两条路径（wlr 的 `MainDevice` / ext 的 `DmabufDevice`），核心逻辑相同：`dev_t` → `DrmNode` → Render 节点路径。回退 `/dev/dri/renderD128`。 + +### 3.4 Dispatch 泛型分发模式 + +三种模式： + +- **A. 完全泛型**：`Dispatch for State` — 共享协议，通常空实现 +- **B. 带状态回调的泛型**：`Dispatch for State` — 需要 `'static`，含实质逻辑 +- **C. 后端专用**：`Dispatch for State` — 非泛型，含后端特有逻辑 + +输出探测通过 `WlOutput` + `ZxdgOutputV1` 协作完成，`PartialOutputInfo` 增量收集直到所有字段填充。每个输出收到两次 `Done` 事件，忽略第一次。 + +--- + +## 4. GPU 编码管道 + +### 4.1 零拷贝数据流 + +``` +GPU 帧池 ─alloc()→ HW Surface + ↓ + av_hwframe_map → DMA-BUF fd + ↓ + zwp_linux_dmabuf → WlBuffer (fd 共享) + ↓ + 合成器直接写入 GPU Surface + ↓ + buffersrc → GPU 滤镜 (crop/scale/transpose) + ↓ + buffersink → 编码器 (send_frame) + ↓ + receive_packet → Muxer → 文件 +``` + +**整条链路中原始帧数据始终在 GPU 内存，不经过 CPU。** + +### 4.2 硬件设备上下文 + +两种硬件加速路径： + +- **VAAPI**：一步创建，直接从 DRM 设备创建 VAAPI 硬件设备上下文 +- **Vulkan**：两步创建，先创建 DRM 上下文，再派生 Vulkan 上下文，中间 DRM 上下文立即释放 + +帧上下文两种用途： +- **Capture**：Vulkan flags = `SAMPLED | TRANSFER_DST`，tiling = `Drm(modifiers)` +- **Enc**：Vulkan flags = `VIDEO_ENCODE_SRC_KHR | TRANSFER_DST`，tiling = `Optimal` + +### 4.3 Vulkan 自引用 Pin 模式 + +`AvHwDevCtxVulkanBuffers` 包含自引用 C 指针链（drm_info → image_fmt_list_info → 内部数组），通过 `Pin>` 解决。`PhantomPinned` 标记 `!Unpin`，`'static` 是对 FFmpeg C API 的"善意谎言"。 + +### 4.4 FFmpeg 滤镜图 + +``` +buffersrc (HW) → crop → scale → [transpose] → [hwdownload] → buffersink +``` + +- `hw_frames_ctx` 绑定是零拷贝的关键 +- crop 使用 `exact=1` workaround +- scale/transpose 按硬件类型选择：`scale_vaapi`/`scale_vulkan`，`transpose_vaapi`/`transpose_vulkan` +- `hwdownload` 仅在软件编码路径添加 + +### 4.5 编码器选择 + +| Codec | VAAPI | Vulkan | +|-------|-------|--------| +| H.264 | `h264_vaapi` | `h264_vulkan` | +| HEVC | `hevc_vaapi` | `hevc_vulkan` | +| VP8/VP9 | `vp8/vp9_vaapi` | 不支持 | +| AV1 | `av1_vaapi` | `av1_vulkan` | + +选择优先级：`--ffmpeg-encoder` 显式指定 > 硬件编码器（尝试 `low_power=1` 后回退）> 通用编码器。 + +### 4.6 EncodePixelFormat 三路派发 + +`Vaapi(Pixel) / Vulkan(Pixel) / Sw(Pixel)` 在编码器格式设置、硬件上下文绑定、滤镜图构建、帧上下文创建四处做三路匹配。 + +`--no-hw` 路径：捕获仍用 GPU（DMA-BUF），编码前 `hwdownload` 到 CPU，软件编码器（x264 自动 `ultrafast`）。 + +--- + +## 5. 状态机与帧生命周期 + +### 5.1 EncConstructionStage 状态机 + +``` + ┌──────────────────┐ + 应用启动 │ ProbingOutputs │ + │ └────────┬─────────┘ + ▼ │ 所有输出探测完毕 +┌───────────────┐ ▼ +│ ProbingOutputs├──→ ┌──────────────────┐ +└───────────────┘ │EverythingButFmt │ + └────────┬─────────┘ + │ negotiate_format() + ▼ + ┌───────────┐ 输出断开 + ┌─────→│ Complete │──────────┐ + │ └─────┬─────┘ │ + │ │ ▼ + │ 格式变化 │ ┌──────────────┐ + │ on_new_ │ │OutputWentAway│ + │ capture_ │ └──────┬───────┘ + │ format() │ │ 同名输出重连 + └────────────┘ │ + ←───────────────────────┘ + + Intermediate 瞬态存在于所有转换箭头处（mem::replace） +``` + +关键转换点： +- **ProbingOutputs → EverythingButFormat**：所有输出探测完毕 +- **EverythingButFormat → Complete**：`negotiate_format()` 创建 EncState +- **Complete → OutputWentAway**：`on_copy_fail()` 检测到输出断开，**保留 enc 丢弃 cap** +- **OutputWentAway → Complete**：同名输出重新出现时创建新 cap 复用旧 enc + +`Intermediate` 瞬态通过 `mem::replace` + `take_enc()` 实现安全所有权转移。`take_enc()` 只允许从 `Complete`/`OutputWentAway` 提取编码器。 + +### 5.2 InFlightSurface 帧生命周期 + +``` + ┌──────┐ queue_alloc_frame() ┌─────────────┐ + │ None │ ───────────────────→ │ AllocQueued │ + └──────┘ └──────┬───────┘ + ↑ │ on_frame_allocd() + │ ▼ + │ ┌───────────┐ + │ │ Allocd │ + │ └─────┬─────┘ + │ │ queue_frame_capture() + │ ▼ + │ ┌──────────────┐ + └────── on_copy_complete ─│ CopyQueued │ + / on_copy_fail └──────────────┘ +``` + +帧级串行化：同一时间只有一帧在途，通过 `assert!` 强制执行。`CopyQueued` 持有 GPU surface、DRM 映射、Wayland 帧和 buffer 四个资源的所有权，拷贝完成后全部释放并启动下一帧。 + +### 5.3 HistoryState 双模式 + +- **RecordingHistory(Duration, VecDeque\)**：环形缓冲，以关键帧为边界裁剪，确保回放可解码 +- **Recording(i64)**：正常写入，PTS 减去偏移量保证起始对齐 + +SIGUSR1 触发 `RecordingHistory → Recording` 转换：先转换状态，再将历史包通过正常录制路径写出。 + +### 5.4 错误恢复 + +`on_copy_fail()` 三个分支按优先级判断： + +1. `output_went_away == true` → 保留编码器，进入 `OutputWentAway` 等待重连 +2. `format_change == true` → 预期失败，重置标志后重新分配帧 +3. 其他 → 未知错误，记录日志后重试 + +### 5.5 动态格式切换 + +捕获格式变化时重建 `frames_rgb`、`video_filter`、`enc_video`、`frames_yuv`，但保留 `octx`、`hw_device_ctx`、`audio`、`history_state`。 + +--- + +## 6. 音频管道与辅助模块 + +### 6.1 音频管道 + +独立线程运行，三阶段构造： + +1. **IncompleteAudioState**：完成编码器选择、设备打开、解码/编码器创建 +2. **AudioHandle**：主线程句柄，含 `Receiver` + `AtomicBool` 控制标志 +3. **AudioState**：音频线程内部状态，move 到独立线程 + +数据流：`音频设备 → 解码 → audio_filter(aformat) → AudioFifo(可选) → 编码 → mpsc → 主线程` + +同步机制：`started` 原子标志在视频首帧时间戳获得后才置 true，确保音视频起点对齐。 + +AudioFifo：解决变长帧编码器需要固定 `frame_size` 的问题。条件判断：编码器不支持 `VARIABLE_FRAME_SIZE` 时创建。 + +### 6.2 帧率限制器 + +VRR 感知设计：引入一帧缓冲延迟判定，避免在 VRR 场景下丢弃"更长时间显示"的帧。 + +``` +on_new_frame(frame, ts): + 第1帧 → 直接通过 + 第2帧 → 存入 on_deck 缓冲 + 第N帧 → 比较缓冲帧与新帧时间戳： + 新帧太近 → 丢弃缓冲帧 + 间隔足够 → 输出缓冲帧，新帧存入 on_deck +``` + +### 6.3 坐标变换 + +处理 Wayland 输出变换（旋转/翻转）对坐标系的影响： + +- **transform_basis()**：8 种变换的基矩阵映射 +- **screen_to_frame()**：矩形从屏幕空间到帧空间 +- **transpose_if_transform_transposed()**：90° 旋转时交换宽高 +- **fit_inside_bounds()**：ROI 越界时安全裁剪 + +### 6.4 主线程事件循环集成 + +主循环中音频包在视频帧处理间隙通过 `try_recv` 非阻塞收取，无需额外事件源。 + +退出时 `EncState::flush()` 依次：刷出 FPS 限制器缓冲帧 → flush 音频线程 → 刷视频过滤器 → 发送编码器 EOF → 写容器 trailer。 + +--- + +## 7. 可移植设计模式 + +从代码库中提取的 10 个可复用设计模式，按复杂度从低到高排列。 + +### 7.1 策略 Trait + 泛型状态（CaptureSource） +**问题**：多后端系统如何在避免运行时动态分发（`dyn Trait`）开销的同时保持类型安全和可扩展性？ +**方案**：定义 `CaptureSource` trait 带关联类型 `Frame`，将整个状态 `State` 泛型参数化。`State` 和 `State` 编译为两个独立单态化类型，后端选择在启动时确定。`alloc_frame()` 返回 `Option` 统一了同步和异步两种帧分配模式。 +**移植要点**： +- 适用后端数量有限（2-5 个）且进程生命周期内不变的场景；需运行时热切换则改用 trait object +- `State` 中 `Sized` 约束必须，因为 `S` 作为字段存储；编译膨胀需注意大型 State 的泛型实例化 +- main.rs 定义 trait 而 cap_*.rs 实现它，形成双向依赖，大型项目应将 trait 提取到独立模块 + +### 7.2 多态枚举状态机（EncConstructionStage） +**问题**：Rust 中如何以零开销实现状态机，同时保证状态转换的类型安全？ +**方案**：`EncConstructionStage` 有 5 个枚举变体（`ProbingOutputs`、`EverythingButFormat`、`Complete`、`OutputWentAway`、`Intermediate`），每个携带该状态所需的数据载荷。`Intermediate` 瞬态 + `mem::replace` 组合解决了部分借用限制：match 解构 `&mut self.enc` 同时给 `self.enc` 赋新值。`take_enc()` 通过消费 `self` 确保只有含编码器的状态才能被提取。 +**移植要点**： +- 3-7 个状态是 enum 状态机甜蜜点；优势是编译期穷尽检查，添加新状态时所有 match 报编译错误 +- `Intermediate` 瞬态必须存在，否则 `mem::replace` 无法满足类型系统要求 +- `Complete` 和 `OutputWentAway` 都持有 `EncState` 但后者丢弃 `cap`，体现"保留昂贵资源、丢弃可重建资源" + +### 7.3 类型安全帧生命周期（InFlightSurface） +**问题**：异步 DMA-BUF 传输涉及多个阶段，如何防止在错误阶段执行操作？ +**方案**：`InFlightSurface` 是 4 状态枚举 `None → AllocQueued → Allocd(S::Frame) → CopyQueued{...} → None`。每个状态携带该阶段特有的资源（`CopyQueued` 持有 GPU surface、DRM 映射、Wayland 帧和 buffer）。状态转换通过 `assert!(matches!(...))` 运行时守护，`take()` 方法（`mem::replace`）提供安全取出并自动重置为 `None`。同一时间只有一帧在途。 +**移植要点**： +- 适用任何"请求→资源就绪→提交操作→操作完成"的异步 I/O 管道 +- 运行时 assert 而非编译期 typestate 是合理权衡：回调驱动的异步场景中编译期类型状态过于复杂 +- RAII 确保 `CopyQueued → None` 路径释放所有资源（DRM 映射、Wayland buffer、帧对象） + +### 7.4 Pin\ 自引用结构（Vulkan Buffers） +**问题**：C 库中的链式结构体（Vulkan pNext 链）内部指针指向同结构其他字段，Rust 中移动会使指针失效，如何安全构建？ +**方案**：`AvHwDevCtxVulkanBuffers` 通过 `PhantomPinned` 标记 `!Unpin`，`Box::pin` 在堆上分配并固定，`get_unchecked_mut` 设置自引用指针。Vulkan 结构体的生命周期标记为 `'static` 作为对 C API 的"善意谎言"，实际受 `Pin>` 控制。unsafe 代码集中在 `new()` 中，使用方完全安全。`chain_ptr()` 根据有无 DRM modifier 返回不同链头。 +**移植要点**： +- 通用模式，适用于 Vulkan、FFmpeg 硬件加速、内核 IOCTL 等涉及自引用 C 结构的场景 +- `'static` 不是真正静态生命周期，而是向 C API 表达"指针在使用期间有效"；确保持有者比 C API 使用时间更长 +- 优于 `ouroboros` crate：手写 `Pin>` 逻辑清晰可控，生成的代码可调试 + +### 7.5 独立线程管道 + 原子标志（音频线程） +**问题**：音频需要持续低延迟处理，视频帧率不固定且受 VRR 影响，如何设计无锁跨线程协作？ +**方案**：音频处理完全隔离在独立线程。`mpsc::channel` 传递已编码 `Packet`，主线程在视频帧处理间隙通过 `try_recv()` 非阻塞收取。`Arc` + `SeqCst` 实现两个控制信号：`started`（视频首帧时间戳获得后置 true，音视频起点对齐）、`flush_flag`（退出通知）。音频线程主循环为 pull 模型，生命周期由输入设备驱动。 +**移植要点**： +- `AtomicBool` 适用于简单布尔信号，比 `Mutex` 高效且不死锁；不适用于需要等待/通知的场景 +- 主循环间隙调用 `try_recv` 是经典的"顺便收取"模式，避免为音频注册额外事件源 +- 适用任何生产者-消费者跨线程场景：传感器采集、网络 I/O 卸载、日志异步写入 + +### 7.6 VRR 感知帧率控制（FpsLimit） +**问题**：VRR 显示器上帧时间戳极不规则，简单"距上帧太近就丢弃"会产生错误决策，如何在不确定的时间戳流中做出正确帧选择？ +**方案**：`FpsLimit` 引入一帧延迟：第一帧直接通过，第二帧存入 `on_deck` 缓冲，从第三帧起用新帧时间戳判断旧帧是否保留。新帧太近则丢弃缓冲帧，间隔足够则输出缓冲帧。目标时间计算中使用 `max` 防止回退，正确处理帧跳跃后恢复。零项目内依赖，可直接复制使用。 +**移植要点**： +- 泛型 `T` 无约束，只做保留/丢弃决策，调用者完全控制帧生命周期 +- 结束时必须调用 `flush()` 取出缓冲中的最后一帧，否则丢帧 +- 一帧延迟对录屏/编码场景可接受，实时交互场景（如游戏输入）需评估 + +### 7.7 泛型 Dispatch 三层分发（Wayland 协议） +**问题**：多后端 Wayland 客户端如何组织 Dispatch 实现，使共享协议代码只写一次、后端专用代码各自独立？ +**方案**：三层分发模式。**A. 完全泛型**：`impl Dispatch for State`，共享协议，通常空实现。**B. 带状态回调泛型**：`impl Dispatch for State`，需 `'static` 约束，含实质状态更新逻辑。**C. 后端专用**：`impl Dispatch for State`，非泛型，在各自后端文件中。Rust trait 系统根据代理类型 × 状态泛型参数 × UserData 自动路由。 +**移植要点**： +- 适用于所有 wayland-client 项目；共享 Dispatch 放 main.rs，专用 Dispatch 放各自后端文件 +- 需关联信息时（如 xdg-output 关联 WlOutput）用 `TypedObjectId` 作为 UserData +- `'static` 约束源自事件循环要求，状态类型必须满足因为回调可能在任意时刻触发 + +### 7.8 三阶段安全构造（IncompleteAudioState） +**问题**：对象需分多阶段初始化且后续阶段依赖前阶段资源，如何在类型系统中安全表达？ +**方案**：三个不同类型表示三个阶段。`IncompleteAudioState` 持有输入设备、解码器、编码器（完成 FFmpeg 流创建）。`finish(self)` 消费不完整状态，创建过滤器、FIFO、通道，组装 `AudioState` 并启动线程，返回 `AudioHandle`（主线程句柄，含 `Receiver` + `AtomicBool`）。`AudioState` 通过 move 语义进入线程。`finish(self)` 而非 `finish(&mut self)` 保证不完整状态被消费后不再存在。 +**移植要点**： +- typestate pattern 变体，用不同类型（非泛型参数）编码状态，优势是不需要泛型 +- 每阶段恰好分配该阶段所需资源；第一阶段打开设备（可能失败）不浪费线程资源 +- 适用 FFmpeg 管线构建、数据库连接池、GPU 资源分配等"先收集信息、再一次性创建"的场景 + +### 7.9 显示器热插拔自动恢复（OutputWentAway） +**问题**：长时间录屏中显示器断连/重连，如何保持编码上下文不丢失并自动恢复录制？ +**方案**：`OutputWentAway` 状态机变体实现完整断连恢复。`wl_registry` 的 `GlobalRemove` 设置 `output_went_away` 标志（延迟到 `on_copy_fail` 时再切换，避免事件处理中途转状态）。转换时通过 `Intermediate` 取出 `enc`（保留编码器），丢弃 `cap`（协议对象已失效），记录等待的输出名称并重新探测。重连时按名称匹配创建新 `CaptureSource`，复用旧编码器继续录制。 +**移植要点**： +- 核心策略：保留昂贵资源（编码器、文件句柄）、丢弃可重建资源（协议对象、设备句柄） +- 名称匹配（如 "DP-1"）而非序号或指针，因为重连后 Wayland 对象 ID 会变化；稳定标识符是热插拔场景关键 +- 适用 USB 摄像头、音频设备、网络连接等可热插拔设备的应用 + +### 7.10 零拷贝 GPU 管道（DMA-BUF → HW Frame → Filter → Encoder） +**问题**：传统录屏将 GPU 帧下载到 CPU 再上传回 GPU 编码，如何实现全程不离开 GPU 内存的零拷贝管线？ +**方案**：GPU 帧池分配硬件表面，`av_hwframe_map` 映射为 DRM PRIME 描述符获取 DMA-BUF fd，注册为 `WlBuffer` 后合成器直接写入 GPU 表面。滤镜图 `buffersrc → crop → scale → [transpose] → buffersink` 全部在 GPU 执行，`hw_frames_ctx` 绑定确保 FFmpeg 识别 GPU 帧。编码器（VAAPI/Vulkan）直接消费 GPU 帧。`EncodePixelFormat` 三路枚举在编码器选择、滤镜构建、帧上下文创建处统一派发，仅 `Sw` 路径添加 `hwdownload`。 +**移植要点**： +- DMA-BUF 桥接是 Linux 特有的；Windows/macOS 需用 D3D11 共享句柄或 IOSurface +- 捕获帧上下文用 `Drm(modifiers)` 匹配合成器，编码帧上下文用 `Optimal` 获最佳性能，滤镜图做格式转换 +- 零拷贝路径失败应降级到 CPU 路径或重试，而非直接崩溃 + +### 模式总结与关联 + +| # | 模式 | 核心机制 | 复杂度 | +|--|------|---------|--------| +| 1 | 策略 Trait + 泛型状态 | `trait + State` 单态化 | 中 | +| 2 | 多态枚举状态机 | `enum + mem::replace + Intermediate` | 中高 | +| 3 | 类型安全帧生命周期 | 4 状态 enum + assert 守护 | 低中 | +| 4 | Pin\ 自引用结构 | `PhantomPinned + Box::pin + unsafe` | 高 | +| 5 | 独立线程管道 + 原子标志 | `mpsc::channel + AtomicBool` | 低 | +| 6 | VRR 感知帧率控制 | 一帧缓冲延迟决策 | 低 | +| 7 | 泛型 Dispatch 三层分发 | `impl Dispatch for State` | 中 | +| 8 | 三阶段安全构造 | 不同类型 × 消费 self | 低中 | +| 9 | 显示器热插拔恢复 | 标志延迟 + 资源分类 + 名称匹配 | 中 | +| 10 | 零拷贝 GPU 管道 | DMA-BUF + HW Frame + GPU Filter | 高 | + +模式围绕"GPU 加速屏幕录制"协同工作：模式 1（策略 Trait）是架构骨架，模式 2（状态机）是运行时驱动核心，模式 10（零拷贝管道）是性能关键路径。模式 1 被模式 2/3/7/9 使用，模式 5（音频线程）使用模式 8（三阶段构造），模式 10 使用模式 4（Pin\）并被模式 6（帧率控制）调节。 diff --git a/build.rs b/build.rs new file mode 100644 index 0000000..f328e4d --- /dev/null +++ b/build.rs @@ -0,0 +1 @@ +fn main() {} diff --git a/docs/superpowers/plans/2026-04-03-wl-webrtc-phase1.md b/docs/superpowers/plans/2026-04-03-wl-webrtc-phase1.md new file mode 100644 index 0000000..1205fa7 --- /dev/null +++ b/docs/superpowers/plans/2026-04-03-wl-webrtc-phase1.md @@ -0,0 +1,2518 @@ +# wl-webrtc Phase 1 Implementation Plan + +> **For agentic workers:** REQUIRED SUB-SKILL: Use superpowers:subagent-driven-development (recommended) or superpowers:executing-plans to implement this plan task-by-task. Steps use checkbox (`- [ ]`) syntax for tracking. + +**Goal:** Build a working Wayland screen → browser streaming pipeline with <50ms LAN latency. + +**Architecture:** mio event loop on main thread handles Wayland capture + GPU encode. tokio runtime handles WebTransport + Web UI. async_channel bridges the two (sync send on mio, async recv on tokio). Browser uses WebCodecs for direct decode. + +**Tech Stack:** Rust, wayland-client, ffmpeg-next (VAAPI/Vulkan), wtransport (WebTransport over HTTP/3), axum + rust-embed (Web UI), WebCodecs (browser) + +**Reference:** Design spec at `docs/superpowers/specs/2026-04-03-wl-webrtc-architecture-design.md`. Source analysis at `analysis.md`. + +--- + +## File Structure + +``` +wl-webrtc/ +├── Cargo.toml +├── build.rs # FFmpeg library detection +├── src/ +│ ├── main.rs # CLI + startup + mio event loop +│ ├── args.rs # CLI argument definitions (clap) +│ ├── cap_ext_image_copy.rs # ext-image-copy-capture backend +│ ├── cap_wlr_screencopy.rs # wlr-screencopy backend +│ ├── avhw.rs # FFmpeg HW device/frame contexts +│ ├── filter.rs # FFmpeg video filter graph +│ ├── transform.rs # Coordinate transforms +│ ├── fps_limit.rs # VRR-aware frame rate limiter +│ ├── state.rs # State machine + CaptureSource trait +│ ├── transport.rs # QUIC/WebTransport server (new) +│ ├── signaling.rs # axum HTTP + static files (new) +│ └── nalu.rs # Annex B NAL unit framing (new) +├── static/ +│ ├── index.html # Web UI shell +│ ├── player.js # WebCodecs decoder + Canvas renderer +│ └── style.css # Minimal styling +└── tests/ + ├── integration_test.rs # End-to-end test harness + └── nalu_test.rs # NAL unit framing tests +``` + +--- + +## Task 1: Project Scaffold + +**Files:** +- Create: `Cargo.toml` +- Create: `build.rs` +- Create: `src/main.rs` +- Create: `src/args.rs` + +- [ ] **Step 1: Create Cargo.toml with all dependencies** + +```toml +[package] +name = "wl-webrtc" +version = "0.1.0" +edition = "2021" +description = "Low-latency Wayland screen sharing via WebTransport" + +[dependencies] +# Wayland screen capture +wayland-client = "0.31" +wayland-protocols = { version = "0.32", features = ["client", "unstable", "staging"] } +wayland-protocols-wlr = { version = "0.3", features = ["client"] } +drm-fourcc = "2" + +# GPU encoding — WARNING: safe API does NOT wrap HW contexts. +# Use ffmpeg_next::ffi directly for AVBufferRef, AVHWFramesContext. +# See wl-screenrec/src/avhw.rs for reference pattern. +ffmpeg-next = "8" + +# WebTransport over HTTP/3 (built on quinn + rustls, self-signed cert support) +wtransport = { version = "0.7", features = ["self-signed"] } + +# Web UI +axum = { version = "0.8", features = ["ws"] } +tower-http = { version = "0.6", features = ["cors"] } +rust-embed = { version = "8", features = ["mime-guess"] } + +# Async runtime +tokio = { version = "1", features = ["full"] } + +# Sync/async bridge (sync send() on mio thread, async recv() on tokio) +async-channel = "2" + +# Event loop +mio = "1" + +# Utilities +clap = { version = "4", features = ["derive"] } +tracing = "0.1" +tracing-subscriber = "0.3" +anyhow = "1" +bytes = "1" +serde = { version = "1", features = ["derive"] } +serde_json = "1" +signal-hook = { version = "0.3", features = ["iterator"] } +base64 = "0.22" +mime_guess = "2" + +```rust +fn main() { + // No custom build steps needed. + // ffmpeg-next's own build.rs handles library detection via pkg-config. +} +``` + +- [ ] **Step 3: Create src/args.rs with CLI argument definitions** + +```rust +use clap::Parser; + +/// Low-latency Wayland screen sharing via WebTransport +#[derive(Parser, Debug)] +#[command(name = "wl-webrtc", version, about)] +pub struct Args { + /// Display output to capture (e.g. "DP-1"). Defaults to first output. + #[arg(short, long)] + pub output: Option, + + /// Region of interest: x,y,w,h (e.g. "100,100,800,600") + #[arg(short, long)] + pub roi: Option, + + /// Target framerate + #[arg(short, long, default_value = "60")] + pub fps: u32, + + /// Port for WebTransport + Web UI + #[arg(short, long, default_value = "8443")] + pub port: u16, + + /// Bind address + #[arg(long, default_value = "0.0.0.0")] + pub bind: String, + + /// Video codec: h264 or hevc + #[arg(long, default_value = "h264")] + pub codec: String, + + /// Hardware encoding backend: vaapi or vulkan + #[arg(long, default_value = "vaapi")] + pub hw_accel: String, + + /// DRM device path (e.g. /dev/dri/renderD128) + #[arg(long)] + pub drm_device: Option, + + /// Target bitrate in bits per second + #[arg(long, default_value = "8000000")] + pub bitrate: u64, + + /// GOP size (keyframe interval in frames) + #[arg(long, default_value = "30")] + pub gop_size: u32, + + /// Enable verbose logging + #[arg(short, long)] + pub verbose: bool, +} +``` + +- [ ] **Step 4: Create minimal src/main.rs that parses args and exits** + +This is a minimal stub. The full implementation is in Task 11. Do NOT add Wayland, transport, or nalu references here — those modules don't exist yet. + +```rust +mod args; + +use args::Args; +use clap::Parser; + +fn main() -> anyhow::Result<()> { + let args = Args::parse(); + + if args.verbose { + tracing_subscriber::fmt().with_max_level(tracing::Level::DEBUG).init(); + } else { + tracing_subscriber::fmt().with_max_level(tracing::Level::INFO).init(); + } + + tracing::info!("wl-webrtc starting"); + tracing::info!("codec={}, hw={}, fps={}, bitrate={}", + args.codec, args.hw_accel, args.fps, args.bitrate); + + // Full implementation is in Task 11 (main event loop wiring). + // This stub only verifies args parsing and logging work. + tracing::warn!("Stub mode — event loop not yet implemented. See Task 11."); + Ok(()) +} +``` + +- [ ] **Step 5: Verify project compiles** + +Run: `cargo build` +Expected: Compiles successfully (may take time for first dependency download) + +- [ ] **Step 6: Commit** + +```bash +git init && git add -A && git commit -m "feat: project scaffold with Cargo.toml, CLI args, main stub" +``` + +--- + +## Task 2: Leaf Modules — transform.rs + +**Files:** +- Create: `src/transform.rs` + +Port coordinate transformation module. This module handles Wayland output transforms (rotation/flip) and ROI clipping. + +**Reference:** Wayland `wl_output` transform enum defines 8 orientations. The transform logic is standard 2D affine math (rotation + reflection matrices). See `wl_output::Transform` in the Wayland protocol spec. + +- [ ] **Step 1: Create src/transform.rs** + +Implement the following coordinate transformation utilities: + +- `Transform` enum — 8 Wayland output transform variants (Normal, _90, _180, _270, Flipped, Flipped90, Flipped180, Flipped270) +- `transform_basis()` — maps Transform to 2x2 matrix (a, b, c, d) +- `screen_to_frame()` — transforms a rectangle from screen space to frame space using transform matrix +- `transpose_if_transform_transposed()` — swaps width/height for 90/270 degree rotations +- `fit_inside_bounds()` — clips ROI rectangle to stay within output bounds + +The module is self-contained with no internal dependencies. Only uses standard library types and `drm_fourcc::DrmFourcc` if needed for format handling. + +Key types: + +```rust +#[derive(Debug, Clone, Copy)] +pub enum Transform { + Normal, + Normal90, + Normal180, + Normal270, + Flipped, + Flipped90, + Flipped180, + Flipped270, +} + +pub struct Rect { + pub x: i32, + pub y: i32, + pub w: i32, + pub h: i32, +} + +pub fn screen_to_frame(transform: Transform, rect: Rect, frame_w: i32, frame_h: i32) -> Rect; +pub fn transpose_if_transform_transposed(transform: Transform, w: i32, h: i32) -> (i32, i32); +pub fn fit_inside_bounds(rect: Rect, bounds_w: i32, bounds_h: i32) -> Rect; +``` + +- [ ] **Step 2: Add `mod transform;` to src/main.rs** + +- [ ] **Step 3: Verify compilation** + +Run: `cargo build` + +- [ ] **Step 4: Commit** + +```bash +git add -A && git commit -m "feat: coordinate transform module for Wayland output transforms" +``` + +--- + +## Task 3: Leaf Modules — fps_limit.rs + +**Files:** +- Create: `src/fps_limit.rs` + +Implement a VRR-aware frame rate limiter. Uses a one-frame-buffer delay strategy to make correct frame-drop decisions in the presence of variable refresh rate displays. + +**Reference:** The one-frame-buffer approach is a standard technique for VRR displays — buffer the current frame, output the previous frame only if enough time has elapsed, otherwise discard the old frame. + +- [ ] **Step 1: Create src/fps_limit.rs** + +Implement the `FpsLimit` struct: + +```rust +pub struct FpsLimit { + on_deck: Option<(T, std::time::Instant)>, + min_interval: std::time::Duration, +} + +impl FpsLimit { + pub fn new(fps: u32) -> Self; + + /// Feed a new frame. Returns: + /// - Some(output_frame) if a buffered frame should be displayed + /// - None if no frame is ready to output yet + /// The returned frame is the PREVIOUS frame (on_deck), not the current one. + /// The current frame is stored in on_deck for next call. + pub fn on_new_frame(&mut self, frame: T, timestamp: std::time::Instant) -> Option; + + /// Call at end of stream to flush the last buffered frame + pub fn flush(&mut self) -> Option; +} +``` + +Logic: +- First frame: return None, store in on_deck +- Second frame onwards: check if interval between on_deck timestamp and new frame >= min_interval + - If yes: output on_deck frame, store new frame in on_deck + - If no: discard on_deck (too close), store new frame in on_deck + +- [ ] **Step 2: Add `mod fps_limit;` to src/main.rs** + +- [ ] **Step 3: Create tests/fps_limit_test.rs with unit tests** + +```rust +#[cfg(test)] +mod tests { + use super::*; + use std::time::{Duration, Instant}; + + #[test] + fn first_frame_is_buffered() { + let mut limiter: FpsLimit = FpsLimit::new(30); + let now = Instant::now(); + let result = limiter.on_new_frame(1u32, now); + assert!(result.is_none()); + } + + #[test] + fn frames_too_close_drops_old() { + let mut limiter: FpsLimit = FpsLimit::new(30); + let now = Instant::now(); + limiter.on_new_frame(1, now); + // Send second frame almost immediately + let result = limiter.on_new_frame(2, now + Duration::from_millis(1)); + // Too close → old frame dropped, new frame buffered + assert!(result.is_none()); + } + + #[test] + fn frames_far_enough_output_old() { + let mut limiter: FpsLimit = FpsLimit::new(30); + let now = Instant::now(); + limiter.on_new_frame(1, now); + // Wait long enough (33ms for 30fps) + let result = limiter.on_new_frame(2, now + Duration::from_millis(40)); + assert_eq!(result, Some(1)); + } + + #[test] + fn flush_returns_last_buffered() { + let mut limiter: FpsLimit = FpsLimit::new(30); + let now = Instant::now(); + limiter.on_new_frame(1, now); + assert_eq!(limiter.flush(), Some(1)); + assert_eq!(limiter.flush(), None); + } +} +``` + +- [ ] **Step 4: Run tests** + +Run: `cargo test fps_limit` +Expected: All 4 tests pass + +- [ ] **Step 5: Commit** + +```bash +git add -A && git commit -m "feat: VRR-aware FPS limiter with unit tests" +``` + +--- + +## Task 4: NAL Unit Framing — nalu.rs + +**Files:** +- Create: `src/nalu.rs` +- Create: `tests/nalu_test.rs` + +New code (not ported). Handles Annex B NAL unit splitting and the framing protocol for QUIC transport. + +- [ ] **Step 1: Create src/nalu.rs with core types** + +```rust +use bytes::Bytes; + +/// A single NAL unit extracted from an Annex B bitstream +pub struct NalUnit { + pub nal_type: u8, + pub data: Bytes, // NAL unit data WITHOUT start codes +} + +/// Identifies frame type for transport framing +#[derive(Debug, Clone, Copy, PartialEq)] +pub enum FrameType { + Keyframe, + Delta, +} + +/// A complete encoded frame ready for transport +#[derive(Clone)] +pub struct EncodedFrame { + pub data: Bytes, + pub pts_us: i64, + pub duration: std::time::Duration, + pub frame_type: FrameType, + pub width: u32, + pub height: u32, +} + +/// Fragment header for QUIC datagram framing +#[derive(Debug, Clone)] +pub struct FragmentHeader { + pub frame_type: u8, // 0x01-0x04, 0x10 + pub frame_id: u32, + pub pts_us: i64, // Presentation timestamp in microseconds (for WebCodecs) + pub seq_num: u16, + pub total_frags: u16, +} + +impl FragmentHeader { + pub const SIZE: usize = 17; // 1 + 4 + 8 + 2 + 2 + + pub const TYPE_KEYFRAME_FRAG: u8 = 0x01; + pub const TYPE_DELTA_FRAG: u8 = 0x02; + pub const TYPE_KEYFRAME_COMPLETE: u8 = 0x03; + pub const TYPE_DELTA_COMPLETE: u8 = 0x04; + pub const TYPE_CODEC_CONFIG: u8 = 0x10; + + pub fn encode(&self) -> [u8; Self::SIZE] { + let mut buf = [0u8; Self::SIZE]; + buf[0] = self.frame_type; + buf[1..5].copy_from_slice(&self.frame_id.to_be_bytes()); + buf[5..13].copy_from_slice(&self.pts_us.to_be_bytes()); + buf[13..15].copy_from_slice(&self.seq_num.to_be_bytes()); + buf[15..17].copy_from_slice(&self.total_frags.to_be_bytes()); + buf + } + + pub fn decode(data: &[u8]) -> anyhow::Result { + if data.len() < Self::SIZE { + return Err(anyhow::anyhow!("fragment header too short")); + } + Ok(Self { + frame_type: data[0], + frame_id: u32::from_be_bytes([data[1], data[2], data[3], data[4]]), + pts_us: i64::from_be_bytes([data[5], data[6], data[7], data[8], data[9], data[10], data[11], data[12]]), + seq_num: u16::from_be_bytes([data[13], data[14]]), + total_frags: u16::from_be_bytes([data[15], data[16]]), + }) + } +} + +/// Splits an encoded frame into fragments suitable for QUIC datagrams +pub struct FrameFragmenter { + max_payload_size: usize, // MTU - header size + frame_counter: u32, +} + +impl FrameFragmenter { + pub fn new(mtu: usize) -> Self { + Self { + max_payload_size: mtu.saturating_sub(FragmentHeader::SIZE), + frame_counter: 0, + } + } + + /// Get the current frame counter value (next frame_id that will be assigned) + pub fn current_frame_id(&self) -> u32 { + self.frame_counter + } + + /// Fragment an encoded frame into QUIC-datagram-sized chunks. + /// Returns Vec of (FragmentHeader, payload) pairs. + /// Keyframes should be sent via reliable stream instead — + /// this method is primarily for delta frames. + pub fn fragment(&mut self, frame: &EncodedFrame) -> Vec<(FragmentHeader, Bytes)> { + let frame_id = self.frame_counter; + self.frame_counter += 1; + + let frag_type = match frame.frame_type { + FrameType::Keyframe => FragmentHeader::TYPE_KEYFRAME_FRAG, + FrameType::Delta => FragmentHeader::TYPE_DELTA_FRAG, + }; + + if frame.data.len() <= self.max_payload_size { + // Fits in a single datagram + let complete_type = match frame.frame_type { + FrameType::Keyframe => FragmentHeader::TYPE_KEYFRAME_COMPLETE, + FrameType::Delta => FragmentHeader::TYPE_DELTA_COMPLETE, + }; + return vec![( + FragmentHeader { + frame_type: complete_type, + frame_id, + pts_us: frame.pts_us, + seq_num: 0, + total_frags: 1, + }, + frame.data.clone(), + )]; + } + + // Need fragmentation + let total_frags = (frame.data.len() + self.max_payload_size - 1) / self.max_payload_size; + let total_frags = total_frags as u16; + + frame.data + .chunks(self.max_payload_size) + .enumerate() + .map(|(i, chunk)| { + ( + FragmentHeader { + frame_type: frag_type, + frame_id, + pts_us: frame.pts_us, + seq_num: i as u16, + total_frags, + }, + Bytes::copy_from_slice(chunk), + ) + }) + .collect() + } +} + +/// H.264 NAL unit type constants +pub mod h264 { + pub const IDR: u8 = 5; + pub const SPS: u8 = 7; + pub const PPS: u8 = 8; +} + +/// HEVC NAL unit type constants +pub mod hevc { + pub const VPS: u8 = 32; + pub const SPS: u8 = 33; + pub const PPS: u8 = 34; + pub const IDR_W_RADL: u8 = 19; + pub const IDR_N_LP: u8 = 20; +} + +/// Find Annex B start code positions in a byte buffer. +/// Returns positions and lengths of start codes (3 or 4 bytes). +pub fn find_annex_b_start_codes(data: &[u8]) -> Vec<(usize, usize)> { + let mut positions = Vec::new(); + let mut i = 0; + while i + 3 <= data.len() { + if data[i..i+3] == [0, 0, 1] { + if i > 0 && data[i-1] == 0 { + positions.push((i - 1, 4)); // 4-byte start code + } else { + positions.push((i, 3)); // 3-byte start code + } + i += 3; + } else { + i += 1; + } + } + positions +} + +/// Determine if an Annex B encoded frame is a keyframe by checking NAL types. +/// For H.264: checks for IDR (type 5) NAL units. +/// For HEVC: checks for IDR_W_RADL (19) or IDR_N_LP (20) NAL types. +pub fn is_keyframe(data: &[u8], is_hevc: bool) -> bool { + let start_codes = find_annex_b_start_codes(data); + if start_codes.is_empty() { + return false; + } + + for i in 0..start_codes.len() { + let nal_start = start_codes[i].0 + start_codes[i].1; + if nal_start >= data.len() { + continue; + } + let nal_type = if is_hevc { + (data[nal_start] >> 1) & 0x3f + } else { + data[nal_start] & 0x1f + }; + + if is_hevc { + if nal_type == hevc::IDR_W_RADL || nal_type == hevc::IDR_N_LP { + return true; + } + } else { + if nal_type == h264::IDR { + return true; + } + } + } + false +} +``` + +- [ ] **Step 2: Add `mod nalu;` to src/main.rs** + +- [ ] **Step 3: Create tests/nalu_test.rs** + +```rust +use wl_webrtc::nalu::*; + +#[test] +fn test_find_start_codes_single_nal() { + // 4-byte start code + 1 byte NAL + let data: &[u8] = &[0x00, 0x00, 0x00, 0x01, 0x65, 0xFF, 0xFF]; + let sc = find_annex_b_start_codes(data); + assert_eq!(sc.len(), 1); + assert_eq!(sc[0], (0, 4)); +} + +#[test] +fn test_find_start_codes_multiple_nals() { + // SPS + PPS + IDR + let data: Vec = [ + &[0x00, 0x00, 0x00, 0x01][..], // start code + &[0x67][..], // SPS (type 7) + &[0x00, 0x00, 0x00, 0x01][..], // start code + &[0x68][..], // PPS (type 8) + &[0x00, 0x00, 0x00, 0x01][..], // start code + &[0x65, 0xFF][..], // IDR (type 5) + ].concat(); + let sc = find_annex_b_start_codes(&data); + assert_eq!(sc.len(), 3); +} + +#[test] +fn test_is_keyframe_h264_idr() { + let data: Vec = [ + &[0x00, 0x00, 0x00, 0x01][..], + &[0x65, 0xFF][..], // IDR NAL type 5 + ].concat(); + assert!(is_keyframe(&data, false)); +} + +#[test] +fn test_is_keyframe_h264_non_idr() { + let data: Vec = [ + &[0x00, 0x00, 0x00, 0x01][..], + &[0x41, 0xFF][..], // Non-IDR slice (type 1) + ].concat(); + assert!(!is_keyframe(&data, false)); +} + +#[test] +fn test_fragment_header_roundtrip() { + let header = FragmentHeader { + frame_type: FragmentHeader::TYPE_DELTA_FRAG, + frame_id: 42, + pts_us: 12345678, + seq_num: 3, + total_frags: 7, + }; + let encoded = header.encode(); + let decoded = FragmentHeader::decode(&encoded).unwrap(); + assert_eq!(decoded.frame_type, header.frame_type); + assert_eq!(decoded.frame_id, header.frame_id); + assert_eq!(decoded.seq_num, header.seq_num); + assert_eq!(decoded.total_frags, header.total_frags); + assert_eq!(decoded.pts_us, header.pts_us); +} + +#[test] +fn test_fragmenter_small_frame() { + let mut fragger = FrameFragmenter::new(1200); + let frame = EncodedFrame { + data: Bytes::from(vec![0u8; 500]), + pts_us: 0, + duration: std::time::Duration::from_secs_f64(1.0 / 60.0), + frame_type: FrameType::Delta, + width: 1920, + height: 1080, + }; + let frags = fragger.fragment(&frame); + assert_eq!(frags.len(), 1); + assert_eq!(frags[0].0.frame_type, FragmentHeader::TYPE_DELTA_COMPLETE); + assert_eq!(frags[0].0.total_frags, 1); +} + +#[test] +fn test_fragmenter_large_frame() { + let mut fragger = FrameFragmenter::new(1200); + let frame = EncodedFrame { + data: Bytes::from(vec![0u8; 5000]), + pts_us: 0, + duration: std::time::Duration::from_secs_f64(1.0 / 60.0), + frame_type: FrameType::Delta, + width: 1920, + height: 1080, + }; + let frags = fragger.fragment(&frame); + assert!(frags.len() > 1); + // All fragments should have the same frame_id + let fid = frags[0].0.frame_id; + for (h, _) in &frags { + assert_eq!(h.frame_id, fid); + } +} +``` + +- [ ] **Step 4: Add `[[test]]` sections to Cargo.toml and wire up tests** + +Add to Cargo.toml: +```toml +[[test]] +name = "nalu_test" +path = "tests/nalu_test.rs" +``` + +- [ ] **Step 5: Run tests** + +Run: `cargo test nalu_test` +Expected: All 7 tests pass + +- [ ] **Step 6: Commit** + +```bash +git add -A && git commit -m "feat: NAL unit framing protocol with Annex B parser and fragmenter" +``` + +--- + +## Task 5: Transport Layer — transport.rs + +**Files:** +- Create: `src/transport.rs` + +New code. WebTransport server using the `wtransport` crate (which provides full HTTP/3 + WebTransport protocol support). The browser's `WebTransport` API requires HTTP/3 with the WebTransport extension — `wtransport` handles all of this internally, including TLS certificate generation and the HTTP/3 handshake. + +**Key decisions:** +1. `wtransport` replaces `quinn` + `h3` + `h3-quinn` — it bundles the full HTTP/3 + WebTransport server stack +2. `async_channel::Receiver` replaces `crossbeam::channel::Receiver` — the async `recv()` method eliminates the sync→async bridge problem +3. TLS is handled internally by `wtransport` (self-signed cert auto-generated) — no manual `TlsConfig` or `rustls` config needed +4. Keyframes → reliable WebTransport stream (`open_uni()`); Delta frames → unreliable datagrams (`send_datagram()`) +5. Single client session in Phase 1 + +**Port architecture:** WebTransport runs over HTTP/3 (UDP). The HTTP static files server (Task 6, axum on TCP) is separate. `player.js` connects to the WebTransport port. Both can share the same port number if desired (HTTP/3 is UDP, axum is TCP), but `player.js` must configure `SERVER_URL` to point to the WebTransport server's address. + +- [ ] **Step 1: Verify transport dependencies in Cargo.toml** + +Dependencies (`wtransport`, `async-channel`) should already be in Cargo.toml from Task 1. If not, add: + +```toml +wtransport = { version = "0.7", features = ["self-signed"] } +async-channel = "2" +``` + +These replace the `quinn`, `rustls`, and `rcgen` deps (remove those if present — `wtransport` handles TLS internally). The `self-signed` feature enables `Identity::self_signed()` for automatic self-signed certificate generation. + +- [ ] **Step 2: Create src/transport.rs** + +```rust +use anyhow::Result; +use async_channel::Receiver; +use std::net::SocketAddr; + +use crate::nalu::{EncodedFrame, FrameFragmenter, FragmentHeader, FrameType}; + +/// Codec configuration extracted from encoder SPS/PPS. +/// Sent to new clients upon session establishment. +pub struct CodecConfig { + pub codec: String, // e.g. "avc1.42E01F" + pub width: u32, + pub height: u32, + pub framerate: u32, +} + +/// Manages WebTransport connections and frame distribution. +/// Uses wtransport crate for full HTTP/3 + WebTransport protocol support. +/// +/// CRITICAL API NOTES (wtransport 0.7): +/// - `wtransport::Endpoint::server(config)` returns `Result>` — use `?` +/// - `endpoint.accept().await` returns `IncomingSession` (NOT a Connection) +/// - `incoming_session.await` returns `SessionRequest` (second await) +/// - `session_request.accept().await` returns `Connection` (third await) +/// - `connection.open_uni().await?.await?` — DOUBLE await for unidirectional streams +/// - `connection.send_datagram(data)` — takes `impl AsRef<[u8]>` (`Vec` works directly) +/// - `connection.receive_datagram().await` — receive datagram +/// - TLS requires `Identity::self_signed()` with `self-signed` feature enabled +pub struct TransportServer { + endpoint: wtransport::endpoint::Endpoint, + frame_rx: Receiver, + codec_config: Option, + last_keyframe: Option, +} + +impl TransportServer { + /// Create a new WebTransport server. + /// + /// Uses Identity::self_signed() for auto-generated TLS certificate. + /// The `self-signed` feature must be enabled in Cargo.toml. + pub fn new(addr: SocketAddr, frame_rx: Receiver) -> Result { + let identity = wtransport::Identity::self_signed(["localhost", "127.0.0.1", "::1"]) + .map_err(|e| anyhow::anyhow!("Failed to generate self-signed certificate: {}", e))?; + + let config = wtransport::ServerConfig::builder() + .with_bind_address(addr) + .with_identity(identity) + .keep_alive_interval(Some(std::time::Duration::from_secs(3))) + .build(); + + let endpoint = wtransport::Endpoint::server(config)?; + + Ok(Self { + endpoint, + frame_rx, + codec_config: None, + last_keyframe: None, + }) + } + + /// Run the transport server loop. Blocks until shutdown. + /// Should be spawned on the tokio runtime. + pub async fn run(mut self) -> Result<()> { + tracing::info!("WebTransport server listening on {}", self.endpoint.local_addr()?); + + let mut fragmenter = FrameFragmenter::new(1200); + let mut session: Option = None; + + loop { + tokio::select! { + // Accept new WebTransport connections + // 3-step chain: accept() -> IncomingSession.await -> SessionRequest.accept().await + incoming = self.endpoint.accept() => { + match Self::accept_session(incoming).await { + Ok(connection) => { + tracing::info!("New WebTransport session from {:?}", connection.remote_address()); + + // Send codec config as first message if available + if let Some(ref config) = self.codec_config { + if let Err(e) = Self::send_codec_config(&connection, config).await { + tracing::warn!("Failed to send codec config: {}", e); + } + } + + // Resend last keyframe if available (so new client can decode immediately) + if let Some(ref keyframe) = self.last_keyframe { + if let Err(e) = Self::send_keyframe_data(&connection, keyframe, &mut fragmenter).await { + tracing::warn!("Failed to send last keyframe to new client: {}", e); + } + } + + session = Some(Session::new(connection)); + } + Err(e) => { + tracing::warn!("Session accept failed: {}", e); + } + } + } + + // Receive encoded frames from capture pipeline (async_channel) + frame = self.frame_rx.recv() => { + match frame { + Ok(frame) => { + // Cache keyframes for new client delivery (EncodedFrame derives Clone) + if frame.frame_type == FrameType::Keyframe { + self.last_keyframe = Some(frame.clone()); + } + + if let Some(s) = &mut session { + if let Err(e) = s.send_frame(&frame, &mut fragmenter).await { + tracing::error!("Frame send error: {}", e); + session = None; + } + } + } + Err(_) => break, // Channel closed — shutdown + } + } + } + } + Ok(()) + } + + /// Accept an incoming session: 3-step async chain + async fn accept_session( + incoming: wtransport::endpoint::IncomingSession, + ) -> Result { + // Step 1: incoming_session.await -> SessionRequest + let session_request = incoming.await?; + tracing::info!( + "Session request: authority='{}', path='{}'", + session_request.authority(), + session_request.path() + ); + // Step 2: session_request.accept().await -> Connection + let connection = session_request.accept().await?; + Ok(connection) + } + + /// Send codec configuration to a client via reliable stream. + /// In Annex B mode, we only send codec name and dimensions. + /// SPS/PPS arrive in-band with each keyframe (via `h264_metadata` BSF with `repeat_sps=1`/`repeat_pps=1`). + async fn send_codec_config( + connection: &wtransport::Connection, + config: &CodecConfig, + ) -> Result<()> { + let mut stream = connection.open_uni().await?.await?; + + // Build JSON config message — NO AVCC description needed in Annex B mode. + // The browser decoder is configured WITHOUT description, which activates Annex B mode. + let config_json = serde_json::json!({ + "type": "codec_config", + "codec": config.codec, + "width": config.width, + "height": config.height, + "framerate": config.framerate, + }); + + // Write type byte + JSON payload + let header = FragmentHeader { + frame_type: FragmentHeader::TYPE_CODEC_CONFIG, + frame_id: 0, + pts_us: 0, + seq_num: 0, + total_frags: 1, + }; + stream.write_all(&header.encode()).await?; + stream.write_all(config_json.to_string().as_bytes()).await?; + stream.finish().await?; + Ok(()) + } + + /// Send a cached keyframe to a new client + async fn send_keyframe_data( + connection: &wtransport::Connection, + frame: &EncodedFrame, + fragmenter: &mut FrameFragmenter, + ) -> Result<()> { + let mut stream = connection.open_uni().await?.await?; + let header = FragmentHeader { + frame_type: FragmentHeader::TYPE_KEYFRAME_COMPLETE, + frame_id: fragmenter.current_frame_id(), + pts_us: frame.pts_us, + seq_num: 0, + total_frags: 1, + }; + stream.write_all(&header.encode()).await?; + stream.write_all(&frame.data).await?; + stream.finish().await?; + Ok(()) + } + + /// Update codec configuration (called from encoder when format changes) + pub fn update_codec_config(&mut self, config: CodecConfig) { + self.codec_config = Some(config); + } +} + +/// A single connected client session +struct Session { + conn: wtransport::Connection, + needs_keyframe: bool, +} + +impl Session { + fn new(conn: wtransport::Connection) -> Self { + Self { conn, needs_keyframe: false } + } + + async fn send_frame( + &mut self, + frame: &EncodedFrame, + fragmenter: &mut FrameFragmenter, + ) -> Result<()> { + match frame.frame_type { + FrameType::Keyframe => { + // Send keyframes via reliable WebTransport stream + // NOTE: open_uni().await?.await? — double await! + let mut stream = self.conn.open_uni().await?.await?; + + // Write fragment header + full data + let header = FragmentHeader { + frame_type: FragmentHeader::TYPE_KEYFRAME_COMPLETE, + frame_id: fragmenter.current_frame_id(), + pts_us: frame.pts_us, + seq_num: 0, + total_frags: 1, + }; + stream.write_all(&header.encode()).await?; + stream.write_all(&frame.data).await?; + stream.finish().await?; + } + FrameType::Delta => { + // Send delta frames via datagrams (unreliable, low latency) + let fragments = fragmenter.fragment(frame); + for (header, payload) in fragments { + let mut datagram = Vec::with_capacity(FragmentHeader::SIZE + payload.len()); + datagram.extend_from_slice(&header.encode()); + datagram.extend_from_slice(&payload); + self.conn.send_datagram(datagram.into())?; + } + } + } + Ok(()) + } +} +``` + +**API notes for the implementer (wtransport 0.7 — VERIFIED against source):** +- `wtransport::Identity::self_signed(["localhost", "127.0.0.1", "::1"])` generates a self-signed TLS certificate (requires `self-signed` feature) +- `wtransport::ServerConfig::builder().with_bind_address(addr).with_identity(identity).build()` creates server config +- `wtransport::Endpoint::server(config)` returns `Result>` — use `?` operator +- `endpoint.accept().await` returns `IncomingSession` — this is the FIRST step +- `incoming_session.await` returns `SessionRequest` — this is the SECOND step +- `session_request.accept().await` returns `Connection` — this is the THIRD step +- `connection.open_uni().await?.await?` opens a unidirectional stream — **DOUBLE await** (first opens QUIC stream, second waits for readiness) +- `connection.send_datagram(bytes)` sends an unreliable datagram (takes `impl Into`) +- `connection.receive_datagram().await` receives a datagram +- `stream.write_all(&data).await?` writes data to a stream +- `stream.finish().await?` closes the stream gracefully +- `self.frame_rx.recv()` is async (from `async_channel`) — no sync→async bridge needed + +- [ ] **Step 3: Add `mod transport;` to src/main.rs** + +- [ ] **Step 4: Verify compilation** + +Run: `cargo build` + +- [ ] **Step 5: Commit** + +```bash +git add -A && git commit -m "feat: WebTransport server with wtransport for browser streaming" +``` + +--- + +## Task 6: Web UI — signaling.rs + static/* + +**Files:** +- Create: `src/signaling.rs` +- Create: `static/index.html` +- Create: `static/player.js` +- Create: `static/style.css` + +- [ ] **Step 1: Create static/index.html** + +```html + + + + + + wl-webrtc + + + +
+
+ +
+ Connecting... +
+
+
+ -- + +
+
+ + + +``` + +- [ ] **Step 2: Create static/style.css** + +```css +* { margin: 0; padding: 0; box-sizing: border-box; } +body { background: #000; color: #fff; font-family: monospace; } +#app { display: flex; flex-direction: column; height: 100vh; } +#video-container { flex: 1; position: relative; display: flex; align-items: center; justify-content: center; } +#video-canvas { max-width: 100%; max-height: 100%; } +#status-overlay { position: absolute; top: 0; left: 0; right: 0; padding: 8px; background: rgba(0,0,0,0.7); text-align: center; } +#controls { display: flex; justify-content: space-between; align-items: center; padding: 8px; background: #111; } +#info { font-size: 12px; color: #aaa; } +button { background: #333; color: #fff; border: 1px solid #555; padding: 6px 16px; cursor: pointer; } +button:hover { background: #444; } +``` + +- [ ] **Step 3: Create static/player.js** + +```javascript +const canvas = document.getElementById('video-canvas'); +const ctx = canvas.getContext('2d'); +const statusEl = document.getElementById('status'); +const infoEl = document.getElementById('info'); +const fullscreenBtn = document.getElementById('fullscreen-btn'); + +// WebTransport server runs on HTTP/3 (UDP) on args.port. +// HTTP static file server runs on TCP on args.port + 1. +// When loaded from the HTTP server, location.port = args.port + 1. +// WebTransport port is one less than the HTTP port. +const WT_PORT = parseInt(location.port) - 1; +const SERVER_URL = `https://${location.hostname}:${WT_PORT}/wt`; + +let decoder = null; +let transport = null; +let frameIdCounter = 0; +let fragmentBuffer = new Map(); // frame_id -> { total, fragments: Map } +let stats = { frames: 0, startTime: 0, latency: 0 }; +let codecConfigured = false; + +// --- Fragment reassembly --- + +const HEADER_SIZE = 17; +const TYPE_KEYFRAME_FRAG = 0x01; +const TYPE_DELTA_FRAG = 0x02; +const TYPE_KEYFRAME_COMPLETE = 0x03; +const TYPE_DELTA_COMPLETE = 0x04; +const TYPE_CODEC_CONFIG = 0x10; + +function parseHeader(data) { + const view = new DataView(data.buffer, data.byteOffset, data.byteLength); + return { + frameType: data[0], + frameId: view.getUint32(1), + // pts_us: bytes 5-12 (i64 big-endian, but JS DataView only supports Float64/Int32) + ptsUs: view.getBigInt64(5), + seqNum: view.getUint16(13), + totalFrags: view.getUint16(15), + }; +} + +function reassembleFrame(header, payload) { + if (header.totalFrags === 1) { + // Complete frame in single packet + return payload; + } + + // Buffer fragment + if (!fragmentBuffer.has(header.frameId)) { + fragmentBuffer.set(header.frameId, { + total: header.totalFrags, + fragments: new Map(), + }); + } + const buf = fragmentBuffer.get(header.frameId); + buf.fragments.set(header.seqNum, payload); + + // Check if complete + if (buf.fragments.size === buf.total) { + const sorted = [...buf.fragments.entries()].sort((a, b) => a[0] - b[0]); + let totalLen = 0; + for (const [, d] of sorted) totalLen += d.byteLength; + const result = new Uint8Array(totalLen); + let offset = 0; + for (const [, d] of sorted) { + result.set(new Uint8Array(d.buffer, d.byteOffset, d.byteLength), offset); + offset += d.byteLength; + } + fragmentBuffer.delete(header.frameId); + return result.buffer; + } + + // Cleanup: evict old incomplete frames to prevent memory leak + const MAX_BUFFER_SIZE = 32; + if (fragmentBuffer.size > MAX_BUFFER_SIZE) { + // Delete oldest entries (lowest frameId) + const sortedIds = [...fragmentBuffer.keys()].sort((a, b) => a - b); + const toDelete = sortedIds.slice(0, fragmentBuffer.size - MAX_BUFFER_SIZE); + for (const id of toDelete) { + fragmentBuffer.delete(id); + } + } + + // Not complete yet + return null; +} + +// --- WebCodecs Decoder --- + +function initDecoder(config) { + decoder = new VideoDecoder({ + output: (frame) => { + canvas.width = frame.codedWidth; + canvas.height = frame.codedHeight; + ctx.drawImage(frame, 0, 0); + frame.close(); + + stats.frames++; + if (stats.startTime === 0) stats.startTime = performance.now(); + const elapsed = (performance.now() - stats.startTime) / 1000; + if (elapsed > 1) { + const fps = (stats.frames / elapsed).toFixed(1); + infoEl.textContent = `${frame.codedWidth}x${frame.codedHeight} | ${fps} fps`; + } + }, + error: (e) => { + console.error('Decoder error:', e); + statusEl.textContent = `Decoder error: ${e.message}`; + }, + }); + + // CRITICAL: Configure WITHOUT description → Annex B mode. + // Per W3C AVC WebCodecs Registration, providing description forces AVC (length-prefixed) + // mode for ALL frames. Since our server sends Annex B (start-code-prefixed), + // we must omit description and rely on in-band SPS/PPS (injected via `h264_metadata` BSF with `repeat_sps=1`/`repeat_pps=1`). + decoder.configure({ + codec: config.codec, + codedWidth: config.width, + codedHeight: config.height, + // NO description field — Annex B mode. SPS/PPS arrive in-band with each keyframe. + }); + codecConfigured = true; + statusEl.textContent = 'Streaming'; +} + +// --- Connection --- + +async function connect() { + statusEl.textContent = 'Connecting...'; + + try { + transport = new WebTransport(SERVER_URL); + await transport.ready; + statusEl.textContent = 'Connected, waiting for stream...'; + + // Read from datagrams for delta frames + readDatagrams(); + + // Read from unidirectional streams for keyframes and codec config + readStreams(); + + } catch (e) { + console.error('Connection failed:', e); + statusEl.textContent = `Connection failed: ${e.message}. Retrying in 3s...`; + setTimeout(connect, 3000); + } +} + +async function readDatagrams() { + const reader = transport.datagrams.readable.getReader(); + try { + while (true) { + const { value, done } = await reader.read(); + if (done) break; + + const header = parseHeader(new Uint8Array(value, 0, HEADER_SIZE)); + const payload = value.slice(HEADER_SIZE); + + handleFrame(header, payload); + } + } catch (e) { + console.error('Datagram read error:', e); + } +} + +async function readStreams() { + try { + const reader = transport.incoming_unidirectional_streams.getReader(); + while (true) { + const { value, done } = await reader.read(); + if (done) break; + + const stream = value; + const data = await readAll(stream); + const header = parseHeader(new Uint8Array(data, 0, HEADER_SIZE)); + const payload = data.slice(HEADER_SIZE); + + handleFrame(header, payload); + } + } catch (e) { + console.error('Stream read error:', e); + } +} + +async function readAll(stream) { + const reader = stream.readable.getReader(); + const chunks = []; + let totalLen = 0; + while (true) { + const { value, done } = await reader.read(); + if (done) break; + chunks.push(value); + totalLen += value.byteLength; + } + const result = new Uint8Array(totalLen); + let offset = 0; + for (const chunk of chunks) { + result.set(new Uint8Array(chunk.buffer, chunk.byteOffset, chunk.byteLength), offset); + offset += chunk.byteLength; + } + return result.buffer; +} + +function handleFrame(header, payload) { + if (header.frameType === TYPE_CODEC_CONFIG) { + // Codec config message — contains codec name and dimensions only. + // No AVCC description needed: we configure in Annex B mode (no `description` field). + // SPS/PPS arrive in-band with each keyframe (injected via `h264_metadata` BSF). + const config = JSON.parse(new TextDecoder().decode(payload)); + initDecoder({ + codec: config.codec, + codedWidth: config.width, + codedHeight: config.height, + }); + return; + } + + if (!codecConfigured || !decoder || decoder.state === 'closed') return; + + const frameData = reassembleFrame(header, payload); + if (!frameData) return; + + const isKeyframe = header.frameType === TYPE_KEYFRAME_COMPLETE || header.frameType === TYPE_KEYFRAME_FRAG; + const chunk = new EncodedVideoChunk({ + type: isKeyframe ? 'key' : 'delta', + // i64 → Number conversion is safe: Number can represent integers up to 2^53 exactly. + // Our PTS starts at 0 and increments by ~16,667μs/frame (60fps). + // Overflow would take ~4.7 million years of continuous streaming. + timestamp: Number(header.ptsUs), + data: frameData, + }); + + if (decoder.state === 'configured') { + decoder.decode(chunk); + } +} + +// --- Fullscreen --- + +fullscreenBtn.addEventListener('click', () => { + if (document.fullscreenElement) { + document.exitFullscreen(); + } else { + document.getElementById('app').requestFullscreen(); + } +}); + +// --- Start --- +connect(); +``` + +- [ ] **Step 4: Create src/signaling.rs** + +```rust +use anyhow::Result; +use axum::{ + body::Body, + extract::State, + http::{header, StatusCode}, + response::{Html, IntoResponse, Response}, + routing::get, + Router, +}; +use rust_embed::Embed; +use std::net::SocketAddr; + +#[derive(Embed)] +#[folder = "static/"] +struct Asset; + +/// Create the axum router for serving static files +pub fn create_router() -> Router { + Router::new() + .route("/", get(index_handler)) + .fallback(static_handler) +} + +async fn index_handler() -> impl IntoResponse { + static_handler(axum::extract::Path("index.html".to_string())).await +} + + +async fn static_handler(path: axum::extract::Path) -> impl IntoResponse { + let path = path.0.trim_start_matches('/'); + let path = if path.is_empty() { "index.html" } else { path }; + + match Asset::get(path) { + Some(file) => { + let mime = mime_guess::from_path(path).first_or_octet_stream(); + Response::builder() + .header(header::CONTENT_TYPE, mime.as_ref()) + .body(Body::from(file.data.to_vec())) + .unwrap() + .into_response() + } + None => StatusCode::NOT_FOUND.into_response(), + } +} + +/// Run the HTTP server for static files on the given address. +/// This should be spawned on the tokio runtime. +pub async fn serve(addr: SocketAddr) -> Result<()> { + let app = create_router(); + let listener = tokio::net::TcpListener::bind(addr).await?; + tracing::info!("HTTP server listening on {}", addr); + axum::serve(listener, app).await?; + Ok(()) +} +``` + +- [ ] **Step 5: Add `mod signaling;` to src/main.rs** + +- [ ] **Step 6: Verify compilation** + +Run: `cargo build` + +- [ ] **Step 7: Commit** + +```bash +git add -A && git commit -m "feat: Web UI with WebCodecs player and static file serving" +``` + +--- + +## Task 7: FFmpeg Hardware Context — avhw.rs + +**Files:** +- Create: `src/avhw.rs` + +Manages FFmpeg hardware device and frame contexts for VAAPI/Vulkan encoding. + +**CRITICAL WARNING:** `ffmpeg-next` crate (v8.x) does NOT provide safe wrappers for `AVBufferRef` (hardware device context) or `AVHWFramesContext` (hardware frame context). The safe API covers codec lookup, encoder configuration, filter graph, and encode/decode flow. ALL hardware context operations MUST use raw FFI via `ffmpeg_next::ffi`. + +**Reference implementation:** See `wl-screenrec/src/avhw.rs` (https://github.com/russelltg/wl-screenrec/blob/main/src/avhw.rs) — this is the closest real-world reference for this exact pattern. + +**API References:** +- ffmpeg-next FFI: `ffmpeg_next::ffi::*` — raw C API bindings +- Key FFI functions: + - `ffi::av_hwdevice_ctx_create(&mut ptr, device_type, device_path, opts, flags)` — create HW device + - `ffi::av_hwdevice_ctx_create_derived(&mut dst, type, src, flags)` — derive HW device (e.g. DRM → VAAPI) + - `ffi::av_hwframe_ctx_alloc(device_ref)` — allocate frame context on device + - `ffi::av_hwframe_ctx_init(frames_ref)` — commit frame context parameters + - `ffi::av_buffer_ref(ptr)` — increment reference count + - `ffi::av_buffer_unref(&mut ptr)` — decrement reference count (for Drop) + - `ffi::av_hwframe_get_buffer(frames_ref, frame, 0)` — allocate HW surface from pool +- FFmpeg VAAPI encoding: https://ffmpeg.org/ffmpeg-codecs.html#vaapi +- VA-API specification: https://01.org/linuxmedia/vaapi + +- [ ] **Step 1: Create src/avhw.rs** + +Implement hardware device and frame context management using ffmpeg-next FFI: + +Key types: + +```rust +use ffmpeg_next as ff; +use ffmpeg_next::ffi as ffi; +use std::ptr; + +/// Hardware encoding backend selection +pub enum HwAccel { + Vaapi, + Vulkan, +} + +/// Encode pixel format — drives three-way dispatch +pub enum EncodePixelFormat { + Vaapi(ff::PixelFormat), + Vulkan(ff::PixelFormat), + Sw(ff::PixelFormat), +} + +/// Holds FFmpeg hardware device context. +/// +/// Wraps a raw *mut AVBufferRef. The ffmpeg-next safe API does NOT expose +/// this type — we use raw FFI pointers with manual Drop. +/// +/// Reference: wl-screenrec/src/avhw.rs — same pattern +pub struct AvHwDevCtx { + ptr: *mut ffi::AVBufferRef, + fmt: ff::PixelFormat, +} + +// SAFETY: AVBufferRef is thread-safe (reference counted internally) +unsafe impl Send for AvHwDevCtx {} + +impl AvHwDevCtx { + /// Create VAAPI device context from DRM device path. + /// + /// Uses raw FFI: ffi::av_hwdevice_ctx_create() + /// Internally calls vaGetDisplayDRM → vaInitialize + pub fn new_vaapi(drm_device: &std::path::Path) -> Result { + let device_cstr = std::ffi::CString::new(drm_device.to_str().unwrap())?; + let mut ptr: *mut ffi::AVBufferRef = ptr::null_mut(); + + let ret = unsafe { + ffi::av_hwdevice_ctx_create( + &mut ptr, + ffi::AVHWDeviceType::AV_HWDEVICE_TYPE_VAAPI, + device_cstr.as_ptr(), + ptr::null_mut(), + 0, + ) + }; + + if ret < 0 { + anyhow::bail!("Failed to create VAAPI device context: error code {}", ret); + } + + Ok(Self { + ptr, + fmt: ff::PixelFormat::VAAPI, + }) + } + + /// Create Vulkan device context from DRM device path. + /// + /// Two-step process via raw FFI: + /// 1. ffi::av_hwdevice_ctx_create(DRM, path) → drm_ctx + /// 2. ffi::av_hwdevice_ctx_create_derived(VULKAN, drm_ctx) → vulkan_ctx + /// 3. Release drm_ctx (derived context shares the GPU device) + /// + /// For self-referential FFmpeg internal structs, Vulkan requires + /// Pin> for stable addresses (see wl-screenrec reference). + pub fn new_vulkan(drm_device: &std::path::Path) -> Result { + let device_cstr = std::ffi::CString::new(drm_device.to_str().unwrap())?; + + // Step 1: Create DRM device context + let mut drm_ptr: *mut ffi::AVBufferRef = ptr::null_mut(); + let ret = unsafe { + ffi::av_hwdevice_ctx_create( + &mut drm_ptr, + ffi::AVHWDeviceType::AV_HWDEVICE_TYPE_DRM, + device_cstr.as_ptr(), + ptr::null_mut(), + 0, + ) + }; + if ret < 0 { + anyhow::bail!("Failed to create DRM device context: error code {}", ret); + } + + // Step 2: Derive Vulkan context from DRM + let mut vk_ptr: *mut ffi::AVBufferRef = ptr::null_mut(); + let ret = unsafe { + ffi::av_hwdevice_ctx_create_derived( + &mut vk_ptr, + ffi::AVHWDeviceType::AV_HWDEVICE_TYPE_VULKAN, + drm_ptr, + 0, + ) + }; + + // Release DRM context regardless of derive result + unsafe { ffi::av_buffer_unref(&mut drm_ptr) }; + + if ret < 0 { + anyhow::bail!("Failed to derive Vulkan device context: error code {}", ret); + } + + Ok(Self { + ptr: vk_ptr, + fmt: ff::PixelFormat::VULKAN, + }) + } + + /// Get raw pointer for use in FFI calls (encoder, filter setup) + pub fn as_ptr(&self) -> *mut ffi::AVBufferRef { + self.ptr + } + + /// Create a new reference (increment refcount) + pub fn ref_clone(&self) -> *mut ffi::AVBufferRef { + unsafe { ffi::av_buffer_ref(self.ptr) } + } +} + +impl Drop for AvHwDevCtx { + fn drop(&mut self) { + if !self.ptr.is_null() { + unsafe { ffi::av_buffer_unref(&mut self.ptr) }; + } + } +} + +/// Holds FFmpeg hardware frame context (used for both capture and encoding). +/// +/// Wraps a raw *mut AVBufferRef pointing to AVHWFramesContext. +/// Must configure via raw pointer cast before calling av_hwframe_ctx_init(). +/// +/// Usage pattern: +/// 1. ffi::av_hwframe_ctx_alloc(device_ctx.as_ptr()) → frames_ref +/// 2. Cast frames_ref data to *mut AVHWFramesContext, set fields +/// 3. ffi::av_hwframe_ctx_init(frames_ref) → commit +pub struct AvHwFrameCtx { + ptr: *mut ffi::AVBufferRef, +} + +unsafe impl Send for AvHwFrameCtx {} + +impl AvHwFrameCtx { + /// Create hardware frame context for DMA-BUF capture surfaces. + /// + /// Uses raw FFI: + /// 1. ffi::av_hwframe_ctx_alloc(hw_device_ctx.as_ptr()) → frames_ref + /// 2. Dereference frames_ref → AVHWFramesContext, set: + /// - format = AV_PIX_FMT_VAAPI (or VULKAN) + /// - sw_format = AV_PIX_FMT_NV12 (or equivalent) + /// - width, height + /// - initial_pool_size = 4 (double buffer + headroom) + /// 3. ffi::av_hwframe_ctx_init(frames_ref) → commit + pub fn for_capture( + hw_device_ctx: &AvHwDevCtx, + width: u32, + height: u32, + sw_format: ff::PixelFormat, + ) -> Result { + let ptr = unsafe { ffi::av_hwframe_ctx_alloc(hw_device_ctx.as_ptr()) }; + if ptr.is_null() { + anyhow::bail!("av_hwframe_ctx_alloc returned null"); + } + + // Configure the frames context via raw pointer + unsafe { + let frames_ctx = (*ptr).data as *mut ffi::AVHWFramesContext; + (*frames_ctx).format = hw_device_ctx.fmt.into(); + (*frames_ctx).sw_format = sw_format.into(); + (*frames_ctx).width = width as i32; + (*frames_ctx).height = height as i32; + (*frames_ctx).initial_pool_size = 4; + } + + let ret = unsafe { ffi::av_hwframe_ctx_init(ptr) }; + if ret < 0 { + unsafe { ffi::av_buffer_unref(&mut ptr as *mut _) }; + anyhow::bail!("av_hwframe_ctx_init failed: error code {}", ret); + } + + Ok(Self { ptr }) + } + + /// Create hardware frame context for encoder input surfaces. + /// Same as for_capture but with encoder-compatible format (typically NV12). + pub fn for_encode( + hw_device_ctx: &AvHwDevCtx, + width: u32, + height: u32, + sw_format: ff::PixelFormat, + ) -> Result { + // Same pattern as for_capture, possibly different pool size + Self::for_capture(hw_device_ctx, width, height, sw_format) + } + + /// Get raw pointer for assignment to encoder/filter hw_frames_ctx + pub fn as_ptr(&self) -> *mut ffi::AVBufferRef { + self.ptr + } +} + +impl Drop for AvHwFrameCtx { + fn drop(&mut self) { + if !self.ptr.is_null() { + unsafe { ffi::av_buffer_unref(&mut self.ptr) }; + } + } +} + +/// Encapsulates the full encoding state +pub struct EncState { + pub enc_video: ff::codec::encoder::Video, + pub frames_rgb: crate::avhw::AvHwFrameCtx, // capture format + pub frames_yuv: crate::avhw::AvHwFrameCtx, // encode format + pub video_filter: ff::filter::Graph, + pub hw_device_ctx: crate::avhw::AvHwDevCtx, + pub starting_timestamp: Option, +} + +impl EncState { + /// Create the full encoding pipeline. + /// + /// Implementation steps: + /// 1. Create AvHwDevCtx (VAAPI or Vulkan based on --hw-accel flag) + /// 2. Create capture frame context (AvHwFrameCtx::for_capture) + /// 3. Create encode frame context (AvHwFrameCtx::for_encode) + /// 4. Create H.264 encoder: + /// - Find codec: `ff::encoder::find_by_name("h264_vaapi")` or `"h264_vulkan"` + /// - Create encoder from codec with hardware device context + /// - Set parameters: width, height, pixel_format (VAAPI/Vulkan), bit_rate, gop_size, time_base + /// - Open encoder + /// 5. Build video filter graph (see filter.rs Task 8) + /// 6. Wrap everything in EncState + pub fn new( + hw_accel: HwAccel, + drm_device: &std::path::Path, + width: u32, + height: u32, + bitrate: u64, + gop_size: u32, + fps: u32, + ) -> Result { + // Step-by-step construction as described above + } +} +``` + +The module must handle: +- VAAPI device creation from DRM render node (`/dev/dri/renderD128`) +- Vulkan device creation (two-step: DRM → Vulkan derivation, then release DRM) +- Hardware frame context creation with correct parameters (capture vs encode) +- Vulkan self-referential `Pin>` pattern for stable FFmpeg struct addresses +- `EncodePixelFormat` three-way dispatch for codec selection, filter building, frame context creation +- DRM device discovery from Wayland protocol data (the DRM device associated with the captured output) + +**Implementation notes:** +- Use raw FFI via `ffmpeg_next::ffi` for ALL hardware context operations: + - `ffi::av_hwdevice_ctx_create()` for VAAPI/DRM device creation + - `ffi::av_hwframe_ctx_alloc()` + `ffi::av_hwframe_ctx_init()` for frame pool creation + - `ffi::av_buffer_ref()` / `ffi::av_buffer_unref()` for reference counting + - `(*ctx_as_mut_ptr()).hw_device_ctx = ffi::av_buffer_ref(...)` to assign HW context +- Use `ff::codec::encoder::find_by_name("h264_vaapi")` to find the VAAPI H.264 encoder +- For the encoder, set `pixel_format` to the hardware format (e.g. `ff::PixelFormat::VA_API`) and `hw_frames_ctx` on the encoder's `codec_context` +- **IMPORTANT**: Use `h264_metadata` bitstream filter with `repeat_sps=1` and `repeat_pps=1` to guarantee SPS/PPS in every IDR frame. Note: `repeat_headers=1` is libx264-only and does NOT work with `h264_vaapi`. +- DRM device path can be discovered from the Wayland compositor's `zwp_linux_dmabuf_feedback_v1` or defaulted to `/dev/dri/renderD128` + +- [ ] **Step 2: Add `mod avhw;` to src/main.rs** + +- [ ] **Step 3: Verify compilation** + +Run: `cargo build` +Note: FFmpeg linking errors are expected if FFmpeg dev libraries aren't installed. Ensure `libavcodec-dev`, `libavformat-dev`, `libavfilter-dev`, `libavutil-dev`, `libswscale-dev` are installed. + +- [ ] **Step 4: Commit** + +```bash +git add -A && git commit -m "feat: FFmpeg hardware device and frame context management" +``` + +--- + +## Task 8: FFmpeg Filter Graph — filter.rs + +**Files:** +- Create: `src/filter.rs` + +Builds the GPU video filter pipeline (crop → scale → transpose) using FFmpeg's libavfilter via ffmpeg-next. + +**API References:** +- ffmpeg-next filter API: https://docs.rs/ffmpeg-next — `filter::Graph`, `filter::Context` +- FFmpeg libavfilter docs: https://ffmpeg.org/ffmpeg-filters.html — `crop`, `scale_vaapi`, `scale_vulkan`, `transpose_vaapi`, `transpose_vulkan` + +- [ ] **Step 1: Create src/filter.rs** + +Implement video filter graph construction: + +```rust +use ffmpeg_next as ff; +use crate::avhw::EncodePixelFormat; + +/// Build the video filter graph for the capture → encode pipeline. +/// +/// Pipeline: buffersrc (HW) → crop → scale → [transpose] → buffersink +/// +/// Implementation: +/// 1. Create `ff::filter::Graph::new()` +/// 2. Add `buffer` source filter with `hw_frames_ctx` set to the capture frame context: +/// - `graph.add_filter(&ff::filter::find("buffer").unwrap(), "in")` +/// - Set params: `video_size`, `pixel_format`, `time_base`, `frame_rate` +/// - Critical: set `hw_frames_ctx` on the buffersrc parameters to enable HW-accelerated filtering +/// 3. Add `crop` filter if ROI specified: +/// - `graph.add_filter(&ff::filter::find("crop").unwrap(), "crop")` +/// - Set params: `x`, `y`, `w`, `h` +/// - Use `exact=1` parameter to avoid rounding issues at edges +/// 4. Add `scale` filter (GPU-accelerated): +/// - VAAPI: `ff::filter::find("scale_vaapi")` — scales in GPU memory +/// - Vulkan: `ff::filter::find("scale_vulkan")` — scales in GPU memory +/// - Set `w` and `h` to encoder input dimensions +/// 5. Add `transpose` filter if output is rotated 90/270 degrees: +/// - VAAPI: `ff::filter::find("transpose_vaapi")` +/// - Vulkan: `ff::filter::find("transpose_vulkan")` +/// - Set `dir` parameter based on transform type +/// 6. Add `buffersink` output filter with `hw_frames_ctx` set to encode frame context: +/// - `graph.add_filter(&ff::filter::find("buffersink").unwrap(), "out")` +/// - Set `hw_frames_ctx` on the buffersink to ensure output is in the encoder's format +/// 7. Link all filters in sequence: `src → crop → scale → [transpose] → sink` +/// 8. Call `graph.validate()` to check the graph is valid +pub fn build_video_filter( + enc: &mut ff::codec::encoder::Video, + frames_rgb: &ff::HardwareFrameContext, + frames_yuv: &ff::HardwareFrameContext, + crop_rect: Option<(i32, i32, i32, i32)>, + needs_transpose: bool, + pixel_format: &EncodePixelFormat, +) -> Result { + // Build graph as described above +} +``` + +**Implementation notes:** +- The filter graph operates entirely on GPU memory — no CPU copies involved +- `hw_frames_ctx` must be set on BOTH buffersrc and buffersink for hardware filtering +- Scale filter names are backend-specific (`scale_vaapi` vs `scale_vulkan`), dispatch via `EncodePixelFormat` +- The `crop` filter with `exact=1` avoids pixel alignment issues at ROI boundaries +- Transpose is only needed for 90/270 degree rotations (check via `transform.rs` helpers) +- After building, call `graph.validate()` to ensure correct linkage + +- [ ] **Step 2: Add `mod filter;` to src/main.rs** + +- [ ] **Step 3: Verify compilation** + +Run: `cargo build` + +- [ ] **Step 4: Commit** + +```bash +git add -A && git commit -m "feat: GPU video filter graph for crop/scale/transpose" +``` + +--- + +## Task 9: Capture Backends — cap_*.rs + +**Files:** +- Create: `src/cap_ext_image_copy.rs` +- Create: `src/cap_wlr_screencopy.rs` + +Implement two Wayland screen capture backends using their respective protocol specifications. Both implement the `CaptureSource` trait. + +**API References:** +- Wayland client crate: https://docs.rs/wayland-client — `Connection`, `GlobalList`, `Dispatch` trait +- wlr-screencopy protocol: `wayland-protocols-wlr` crate — `zwlr_screencopy_manager_v1`, `zwlr_screencopy_frame_v1` +- ext-image-copy-capture protocol: `wayland-protocols` crate (with `staging` feature) — `ext_image_copy_capture_manager_v1`, `ext_image_copy_capture_session_v1`, `ext_image_copy_capture_frame_v1` +- DMA-BUF protocol: `zwp_linux_dmabuf_v1` (in `wayland-protocols` crate) — buffer creation and format negotiation + +- [ ] **Step 1: Define CaptureSource trait in src/state.rs (create minimal file)** + +```rust +use bytes::Bytes; +use wayland_client::protocol::wl_output::WlOutput; + +/// Unified interface for screen capture backends +pub trait CaptureSource: Sized + 'static { + /// Frame type specific to this backend + type Frame; + + /// Create a new capture source from Wayland globals and target output. + /// + /// Implementation: Use `wayland_client::globals::GlobalList` to bind the protocol global, + /// then create a capture session targeting the specified `WlOutput`. + fn new( + gm: &wayland_client::globals::GlobalList, + output: &WlOutput, + output_info: &crate::OutputInfo, + ) -> Result; + + /// Allocate a frame for capture. Returns Some(frame) for synchronous + /// backends (ext-image-copy), None for async (wlr-screencopy). + fn alloc_frame(&mut self) -> Option; + + /// Submit DMA-BUF buffer to compositor for capture. + /// + /// Implementation: Create a `wl_buffer` from the DMA-BUF fd using `zwp_linux_dmabuf_v1`, + /// then pass it to the capture protocol's capture request. + fn queue_copy(&self, buffer: wayland_client::protocol::wl_buffer::WlBuffer); + + /// Callback when frame is done being used + fn on_done_with_frame(&self, frame: Self::Frame); +} +``` + +- [ ] **Step 2: Create src/cap_ext_image_copy.rs** + +Implement ext-image-copy-capture backend (~240 lines). + +**Protocol overview** (ext-image-copy-capture-v1): +- `ext_image_copy_capture_manager_v1` — global for creating sessions +- `ext_image_copy_capture_session_v1` — session object, created for a specific output +- `ext_image_copy_capture_frame_v1` — per-frame capture object +- Session-level format negotiation (not per-frame) — format is negotiated once and reused +- Synchronous allocation: `alloc_frame()` returns `Some(frame)` immediately +- Supports real modifier list via `zwp_linux_dmabuf_feedback_v1` (not hardcoded LINEAR) + +**Implementation steps:** +1. Bind `ext_image_copy_capture_manager_v1` global from `GlobalList` +2. Create session for target output: `manager.create_session(output)` +3. Implement `Dispatch` trait for `ext_image_copy_capture_session_v1`: + - Handle `format` event — receive negotiated DMA-BUF format and modifier + - Handle `constraints` event — receive size and modifier constraints +4. Implement `Dispatch` trait for `ext_image_copy_capture_frame_v1`: + - Handle `ready` event — frame data written to DMA-BUF + - Handle `failed` event — capture failed +5. `alloc_frame()` — allocate from hardware frame pool, return `Some(frame)` +6. `queue_copy()` — create `wl_buffer` via `zwp_linux_dmabuf_v1::create_params`, pass DMA-BUF fd, submit frame capture + +Key types: +- `CapExtImageCopy` struct holding session, format state, constraints +- `ExtImageCopyFrame` — the frame type for this backend + +- [ ] **Step 3: Create src/cap_wlr_screencopy.rs** + +Implement wlr-screencopy backend (~165 lines). + +**Protocol overview** (zwlr-screencopy-unstable-v1): +- `zwlr_screencopy_manager_v1` — global for creating frame captures +- `zwlr_screencopy_frame_v1` — per-frame capture object (created fresh each frame) +- Per-frame format negotiation — format is negotiated for each capture +- Asynchronous allocation: `alloc_frame()` returns `None` — frame object triggers allocation +- Uses hardcoded `DrmModifier::LINEAR` for buffer creation + +**Implementation steps:** +1. Bind `zwlr_screencopy_manager_v1` global from `GlobalList` +2. Implement `Dispatch` trait for `zwlr_screencopy_frame_v1`: + - Handle `buffer` event — receive format, width, height, stride + - Handle `ready` event — frame data written to buffer, receive timestamp + - Handle `failed` event — capture failed +3. For each frame: + - Create new `zwlr_screencopy_frame_v1` via `manager.capture_output(output)` + - On `buffer` event: negotiate format, create DMA-BUF buffer + - On `ready` event: frame is complete +4. `alloc_frame()` — returns `None` (async; frame object is the trigger) +5. `queue_copy()` — submit the DMA-BUF buffer to the frame object + +Key types: +- `CapWlrScreencopy` struct holding manager, frame state +- `WlrScreencopyFrame` — the frame type + +- [ ] **Step 4: Add modules to src/main.rs** + +```rust +mod cap_ext_image_copy; +mod cap_wlr_screencopy; +mod state; +``` + +- [ ] **Step 5: Verify compilation** + +Run: `cargo build` +Note: Wayland protocol code may require protocol XML files. Check wayland-protocols crate features. + +- [ ] **Step 6: Commit** + +```bash +git add -A && git commit -m "feat: Wayland capture backends (ext-image-copy + wlr-screencopy)" +``` + +--- + +## Task 10: State Machine — state.rs + +**Files:** +- Modify: `src/state.rs` (expand from Task 9 minimal version) + +Implement the full state machine with `EncConstructionStage`, `InFlightSurface`, and the `State` struct. + +**Design reference:** See architecture spec §4 for state diagrams and transitions. + +- [ ] **Step 1: Expand src/state.rs with full state machine** + +```rust +use crate::avhw::EncState; +use crate::nalu::EncodedFrame; +use crate::CaptureSource; +use async_channel::Sender; + +/// Output information collected during probing +pub struct OutputInfo { + pub name: String, + pub transform: crate::transform::Transform, + pub width: i32, + pub height: i32, + pub scale: f64, +} + +/// Partial output info during the ProbingOutputs stage +pub struct PartialOutputInfo { + pub name: Option, + pub transform: Option, + pub width: Option, + pub height: Option, + pub scale: Option, + pub wl_output: wayland_client::protocol::wl_output::WlOutput, +} + +impl PartialOutputInfo { + pub fn is_complete(&self) -> bool { + self.name.is_some() && self.transform.is_some() + && self.width.is_some() && self.height.is_some() + } + + pub fn into_output_info(self) -> Option { + Some(OutputInfo { + name: self.name?, + transform: self.transform?, + width: self.width?, + height: self.height?, + scale: self.scale.unwrap_or(1.0), + }) + } +} + +/// State machine for encoder construction +pub enum EncConstructionStage { + /// Discovering Wayland outputs + ProbingOutputs { + outputs: Vec, + }, + /// Outputs known, waiting for format negotiation + EverythingButFmt { + output_info: OutputInfo, + hw_device_ctx: crate::avhw::AvHwDevCtx, + cap: S, + }, + /// Fully operational — streaming + Streaming { + output_info: OutputInfo, + enc: EncState, + cap: S, + frame_tx: Sender, + }, + /// Output disconnected, waiting for reconnection + OutputWentAway { + output_name: String, + enc: EncState, + frame_tx: Sender, + }, + /// Transient state during transitions (mem::replace target) + Intermediate, +} + +impl EncConstructionStage { + /// Extract EncState, consuming self. Used during state transitions + /// that preserve the encoder while discarding capture objects. + pub fn take_enc(self) -> Option<(EncState, Sender)> { + match self { + Self::Streaming { enc, frame_tx, .. } => Some((enc, frame_tx)), + Self::OutputWentAway { enc, frame_tx, .. } => Some((enc, frame_tx)), + _ => None, + } + } +} + +/// Frame capture lifecycle — tracks the state of the single in-flight surface. +/// At most one frame is being processed at any time to prevent buffer exhaustion. +pub enum InFlightSurface { + /// No frame in flight — ready to start next capture + None, + /// Frame allocation requested, waiting for GPU surface + AllocQueued, + /// Surface allocated from hardware frame pool + Allocd(S::Frame), + /// Buffer submitted to compositor, waiting for capture completion + CopyQueued { + surface: ffmpeg_next::frame::Video, + drm_map: ffmpeg_next::ffi::AVDRMFrameDescriptor, // DMA-BUF mapping descriptor + frame: S::Frame, + buffer: wayland_client::protocol::wl_buffer::WlBuffer, + }, +} + + /// Global state parameterized by capture backend + pub struct State { + pub enc: EncConstructionStage, + pub in_flight_surface: InFlightSurface, + pub starting_timestamp: Option, + pub args: crate::args::Args, + pub frame_tx: Sender, + pub errored: bool, + pub output_went_away: bool, + pub format_change: bool, + pub gm: wayland_client::globals::GlobalList, + pub xdg_output_manager: Option, + pub fps_limit: Option>, + } + +impl State { + /// Create initial state in ProbingOutputs stage + pub fn new( + gm: wayland_client::globals::GlobalList, + args: crate::args::Args, + frame_tx: Sender, + qh: &wayland_client::QueueHandle>, + ) -> Self { + Self { + enc: EncConstructionStage::ProbingOutputs { + outputs: Vec::new(), + }, + in_flight_surface: InFlightSurface::None, + starting_timestamp: None, + args, + frame_tx, + errored: false, + output_went_away: false, + format_change: false, + gm, + xdg_output_manager: None, + fps_limit: None, + } + } + + /// Frame captured successfully — run through filter + encode, send to transport. + /// + /// Pipeline: captured HW frame → video_filter → encoder → EncodedFrame → channel + pub fn on_copy_complete(&mut self) -> anyhow::Result<()> { + // 1. Extract the captured frame from InFlightSurface + // - assert!(matches!(in_flight_surface, CopyQueued{..})) + // - Take ownership of surface, mark InFlightSurface::None + // + // 2. Push captured HW frame into filter graph (buffersrc) + // - enc.video_filter.get("in").source().add(&surface) + // + // 3. Pull filtered frame from filter graph (buffersink) + // - enc.video_filter.get("out").sink().frame(&mut filtered) + // + // 4. Send to encoder + // - enc.enc_video.send_frame(&filtered_frame) + // + // 5. Receive encoded packet + // - enc.enc_video.receive_packet(&mut packet) + // - Loop until receive_packet returns EAGAIN + // + // 6. Check if keyframe via NAL type inspection (crate::nalu::is_keyframe) + // + // 7. Wrap as EncodedFrame and send through frame_tx + // - IMPORTANT: Use try_send(), NOT send() or send_blocking()! + // try_send() is non-blocking: returns Err(TrySendError::Full(_)) if channel full. + // On full channel, log and drop the frame (acceptable for real-time streaming). + // Do NOT use send_blocking() — it would stall the mio capture pipeline. + // - frame_tx.try_send(EncodedFrame { + // data, pts_us, duration: 1_000_000/fps μs, frame_type, width, height + // }) + // + // 8. Return InFlightSurface to None (ready for next frame) + Ok(()) + } + + /// Frame capture failed — handle errors. + pub fn on_copy_fail(&mut self) { + // 1. Check output_went_away flag + // - If true: transition to OutputWentAway (preserve encoder + transport, drop capture) + // 2. Check format_change flag + // - If true: rebuild filter + frame contexts (preserve device ctx + transport) + // 3. Otherwise: log error, set errored flag + } + + /// Frame allocated — create DMA-BUF buffer and queue capture. + pub fn on_frame_allocd(&mut self, frame: S::Frame) { + // 1. Create wl_buffer from frame's DMA-BUF fd using zwp_linux_dmabuf_v1 + // 2. Queue capture: cap.queue_copy(buffer) + // 3. Transition InFlightSurface: Allocd → CopyQueued + } + + /// Initiate frame capture cycle — call when in Streaming state and no frame in flight. + pub fn queue_alloc_frame(&mut self) { + // 1. assert!(matches!(in_flight_surface, None)) + // 2. Call cap.alloc_frame() + // - For ext-image-copy: returns Some(frame) → immediately call on_frame_allocd + // - For wlr-screencopy: returns None → set InFlightSurface::AllocQueued + // 3. Transition InFlightSurface: None → AllocQueued or Allocd + } + + /// Negotiate DMA-BUF format with compositor. + /// Called during EverythingButFmt → Streaming transition. + pub fn negotiate_format(&mut self) -> anyhow::Result<()> { + // 1. Determine capture format from compositor feedback + // 2. Create hardware frame contexts (capture + encode) + // 3. Build video filter graph + // 4. Create encoder with negotiated parameters + // 5. Transition EverythingButFmt → Streaming + Ok(()) + } +} +``` + +- [ ] **Step 2: Verify compilation** + +Run: `cargo build` + +- [ ] **Step 3: Commit** + +```bash +git add -A && git commit -m "feat: state machine with EncConstructionStage and InFlightSurface" +``` + +--- + +## Task 11: Main Event Loop — main.rs + +**Files:** +- Modify: `src/main.rs` (replace stub with full implementation) + +Wire everything together: CLI → Wayland connection → state machine → mio event loop → tokio runtime. + +- [ ] **Step 1: Replace src/main.rs with full implementation** + +```rust +mod args; +mod avhw; +mod cap_ext_image_copy; +mod cap_wlr_screencopy; +mod filter; +mod fps_limit; +mod nalu; +mod signaling; +mod state; +mod transform; +mod transport; + +use args::Args; +use cap_ext_image_copy::CapExtImageCopy; +use cap_wlr_screencopy::CapWlrScreencopy; +use clap::Parser; +use async_channel; +use mio::{Events, Interest, Poll, Token}; +use state::{State, EncConstructionStage}; +use std::os::unix::io::AsRawFd; + +const TOKEN_WAYLAND: Token = Token(0); +const TOKEN_QUIT: Token = Token(1); + +fn main() -> anyhow::Result<()> { + let args = Args::parse(); + + // Initialize logging + if args.verbose { + tracing_subscriber::fmt().with_max_level(tracing::Level::DEBUG).init(); + } else { + tracing_subscriber::fmt().with_max_level(tracing::Level::INFO).init(); + } + + // Create async_channel for encoded frames (capture pipeline → transport) + // async_channel provides both sync try_send() and async recv() + let (frame_tx, frame_rx) = async_channel::bounded::(16); + + // Spawn tokio runtime for transport + web UI + let tokio_rt = tokio::runtime::Builder::new_multi_thread() + .enable_all() + .build()?; + + let bind_addr = format!("{}:{}", args.bind, args.port).parse::()?; + let http_addr = format!("{}:{}", args.bind, args.port + 1).parse::()?; + + // Start transport server on tokio + tokio_rt.spawn(async move { + if let Err(e) = async { + let server = transport::TransportServer::new(bind_addr, frame_rx)?; + server.run().await + } + .await + { + tracing::error!("Transport server error: {}", e); + } + }); + + // Start HTTP server for Web UI on tokio + tokio_rt.spawn(async move { + if let Err(e) = signaling::serve(http_addr).await { + tracing::error!("HTTP server error: {}", e); + } + }); + + // Connect to Wayland compositor + // wayland-client 0.31 API: Connection (not deprecated Display) + let conn = wayland_client::Connection::connect_to_env()?; + + // Use registry_queue_init for initial global discovery with () state. + // This returns (GlobalList, EventQueue<()>). + let (gm, mut probe_queue) = wayland_client::globals::registry_queue_init::<()>(&conn)?; + let _probe_qh = probe_queue.handle(); + + // Determine which capture backends are available + // Priority: ext-image-copy-capture > wlr-screencopy + let has_ext: bool = gm.instances().any(|(iface, _)| { + iface == "ext_image_copy_capture_manager_v1" + }); + let has_wlr: bool = gm.instances().any(|(iface, _)| { + iface == "zwlr_screencopy_manager_v1" + }); + + if !has_ext && !has_wlr { + anyhow::bail!( + "No supported screen capture protocol found. \ + Need ext-image-copy-capture-v1 or zwlr-screencopy-unstable-v1." + ); + } + + tracing::info!( + "Capture backends: ext-image-copy={}, wlr-screencopy={}", + has_ext, has_wlr + ); + + // Set up mio poll for Wayland fd + signals + let mut poll = Poll::new()?; + let mut events = Events::with_capacity(1024); + + // Register Wayland fd with mio + let wl_fd = conn.fd(); + let mut wl_event_source = mio::unix::SourceFd(&wl_fd); + poll.registry().register( + &mut wl_event_source, + TOKEN_WAYLAND, + Interest::READABLE, + )?; + + // Set up signal handling via signal-hook + mio + let mut signals = signal_hook::iterator::Signals::new([ + signal_hook::consts::SIGINT, + signal_hook::consts::SIGTERM, + ])?; + let signal_fd = signals.as_raw_fd(); + let mut signal_source = mio::unix::SourceFd(&signal_fd); + poll.registry().register( + &mut signal_source, + TOKEN_QUIT, + Interest::READABLE, + )?; + + // Monomorphized backend selection: run the event loop with the chosen backend. + // Each branch creates a typed EventQueue> and runs the same event loop. + // This avoids the CaptureBackend enum dispatch problem — the Wayland Dispatch trait + // requires compile-time monomorphization (State vs State). + if has_ext { + run_event_loop::(conn, gm, args, frame_tx, &mut poll, &mut events)?; + } else { + run_event_loop::(conn, gm, args, frame_tx, &mut poll, &mut events)?; + } + + // Cleanup + tokio_rt.shutdown_background(); + tracing::info!("wl-webrtc stopped"); + Ok(()) +} + +/// Generic event loop, monomorphized per capture backend. +/// Both branches compile the same event loop code with the concrete State type. +fn run_event_loop( + conn: wayland_client::Connection, + gm: wayland_client::globals::GlobalList, + args: Args, + frame_tx: async_channel::Sender, + poll: &mut Poll, + events: &mut Events, +) -> anyhow::Result<()> { + // Create typed event queue for the actual event loop. + // wayland-client 0.31: Connection::new_event_queue::() creates EventQueue + let mut event_queue = conn.new_event_queue::>(); + let qh = event_queue.handle(); + + // Create initial state in ProbingOutputs stage + let mut state = State::::new(gm, args, frame_tx, &qh); + + tracing::info!("wl-webrtc event loop starting (backend: {})", std::any::type_name::()); + + // Main event loop + let mut running = true; + 'main: loop { + if !running { break 'main; } + + // Poll with timeout to prevent blocking forever + poll.poll(events, Some(std::time::Duration::from_millis(100)))?; + + for event in events.iter() { + match event.token() { + TOKEN_QUIT => { + tracing::info!("Shutdown signal received"); + running = false; + break 'main; + } + TOKEN_WAYLAND => { + // Dispatch Wayland events — this drives: + // output probing, format negotiation, frame capture callbacks + event_queue.dispatch_pending(&mut state, |_, _, _| {})?; + } + _ => {} + } + } + + // After dispatch, initiate next frame capture if ready + if matches!(state.enc, EncConstructionStage::Streaming { .. }) + && matches!(state.in_flight_surface, state::InFlightSurface::None) + { + state.queue_alloc_frame(); + } + + // Check for fatal errors + if state.errored { + tracing::error!("Fatal error in capture pipeline, exiting"); + break; + } + + // Flush any pending Wayland requests + event_queue.flush()?; + } + + Ok(()) +} +``` + +**Implementation notes:** + +1. **Wayland-client 0.31 API**: Uses `Connection::connect_to_env()` (not deprecated `Display`), `registry_queue_init()` for global discovery, and `conn.new_event_queue::()` for typed event queues. See `wl-screenrec/src/main.rs` for the reference pattern. + +2. **Monomorphized backend selection** (NOT enum dispatch): The `run_event_loop::()` function is generic over the capture backend. At startup, we call it with either `CapExtImageCopy` or `CapWlrScreencopy` based on available Wayland globals. This is the same pattern wl-screenrec uses — the Wayland `Dispatch` trait requires compile-time monomorphization. The `CaptureBackend` enum dispatch pattern from earlier drafts was incorrect because `Dispatch` implementations are per-`State` type, not per-enum-variant. + +3. **Signal handling** uses `signal-hook` crate with mio integration. SIGINT/SIGTERM trigger clean shutdown. + +4. **The event loop** is straightforward: + - `mio::poll` blocks until Wayland fd is readable or signal arrives + - `event_queue.dispatch_pending` processes all pending Wayland events (frame captures, output changes, etc.) + - After dispatch, check if a new frame capture should be initiated + - 100ms timeout prevents indefinite blocking if no events arrive + +5. **Dependency**: `signal-hook` already in Cargo.toml from Task 1. + +- [ ] **Step 2: Verify full project compiles** + +Run: `cargo build` + +- [ ] **Step 3: Commit** + +```bash +git add -A && git commit -m "feat: main event loop with Wayland capture and tokio transport" +``` + +--- + +## Task 12: Integration Testing + +**Files:** +- Create: `tests/integration_test.rs` + +- [ ] **Step 1: Create integration test scaffolding** + +```rust +/// Integration test: verify the full pipeline can start. +/// This test requires: +/// - A running Wayland compositor (or CI with weston headless) +/// - FFmpeg with VAAPI support (or software fallback) +/// - A display to capture +/// +/// The test is tagged #[ignore] for CI environments without hardware. + +#[cfg(test)] +mod tests { + use std::process::Command; + + #[test] + #[ignore] + fn test_binary_starts() { + // Verify the binary starts and doesn't crash immediately + let output = Command::new("cargo") + .args(["run", "--", "--help"]) + .output() + .expect("Failed to run wl-webrtc"); + + assert!(output.status.success()); + let stdout = String::from_utf8_lossy(&output.stdout); + assert!(stdout.contains("wl-webrtc")); + assert!(stdout.contains("port")); + assert!(stdout.contains("codec")); + } + + #[test] + fn test_transport_server_binds() { + // Test that QUIC server can bind to a port + // (without Wayland, just the transport layer) + let (tx, rx) = async_channel::bounded(16); + + // This should succeed in creating a QUIC endpoint + // (tested in a separate thread since it needs tokio) + let rt = tokio::runtime::Runtime::new().unwrap(); + rt.block_on(async { + // Can't fully test without Wayland, but verify types compile + let _ = tx; + }); + } +} +``` + +- [ ] **Step 2: Run unit tests** + +Run: `cargo test` +Expected: fps_limit tests pass, nalu tests pass, integration tests ignored + +- [ ] **Step 3: Verify full build in release mode** + +Run: `cargo build --release` +Expected: Compiles successfully + +- [ ] **Step 4: Final commit** + +```bash +git add -A && git commit -m "feat: integration test scaffolding and release build verification" +``` + +--- + +## Self-Review Checklist + +- [x] **Spec coverage**: Every module in spec Section 2.3 has a corresponding task +- [x] **Placeholder scan**: No TBD/TODO in step descriptions — all steps have concrete code or explicit implementation guidance referencing official protocol specs and public API documentation +- [x] **Known gaps**: + - Task 7 (avhw.rs) and Task 8 (filter.rs) require deep FFmpeg API knowledge. Code shown is structural, not complete implementation. The actual implementation requires working with raw FFI bindings via `ffmpeg_next::ffi` for hardware context management (AVBufferRef, AVHWFramesContext). See `wl-screenrec/src/avhw.rs` for reference pattern. + - Task 11 (main.rs) uses monomorphized `run_event_loop::()` generic function — one branch per capture backend. This avoids the CaptureBackend enum dispatch problem (Wayland `Dispatch` trait requires compile-time monomorphization). + - `wtransport` crate handles HTTP/3 + WebTransport protocol internally. Browser `new WebTransport()` works directly — no manual h3 integration needed. + +**Implementation complexity notes**: +- `ffmpeg-next` crate (v8.1.0) does NOT provide safe wrappers for `AVBufferRef` (hardware device context) or `AVHWFramesContext` (hardware frame context). These operations require using the raw FFI bindings via `ffmpeg_next::ffi`. Specifically: + `ffi::av_hwdevice_ctx_create()`, `ffi::av_hwframe_ctx_alloc()`, `ffi::av_hwframe_ctx_init()`, `ffi::av_hwframe_transfer_data()` — transfers between DMA-BUF and VAAPI surfaces. + `(*ctx.as_mut_ptr()).hw_device_ctx = ffi::av_buffer_ref(...)` to assign HW context to encoder/filter. The safe API covers: codec lookup, encoder configuration, filter graph, and encode/decode flow. +- **Encoder MUST use `h264_metadata` BSF** with `repeat_sps=1` and `repeat_pps=1` to guarantee SPS/PPS in every IDR frame. Note: `repeat_headers=1` is libx264-only and does NOT work with `h264_vaapi`. Required for WebCodecs Annex B mode on the browser side. +- Task 11 (main.rs) uses monomorphized `run_event_loop::()` — NOT enum dispatch. Wayland's `Dispatch` trait requires compile-time monomorphization. See wl-screenrec for the reference pattern. +- `async_channel::bounded(16)` provides both sync `try_send()` (from mio main thread) and async `recv()` (from tokio transport). Main thread uses `try_send()` — if channel is full, the frame is dropped and logged. This prevents GPU pipeline stalls. **Do NOT use `send_blocking()`** — it would stall the mio capture pipeline. +- `wtransport` crate (v0.7) provides complete WebTransport-over-HTTP/3 server. No raw quinn or h3 integration needed. Browser `new WebTransport(url)` works directly. +- **WebCodecs Annex B mode**: Browser configures `VideoDecoder` WITHOUT `description` field. Per W3C AVC WebCodecs Registration, omitting `description` activates Annex B mode — all `EncodedVideoChunk` data must use start-code-prefixed NAL units (which our encoder outputs). The `description` field forces AVC (length-prefixed) mode — do NOT provide it. + +## Implementation Gap Notes + +> **WARNING**: The following tasks require significant implementation work not fully specified in the code blocks above. An implementing agent MUST consult the referenced source code for complete patterns. + +### Task 7 (avhw.rs) — FFmpeg FFI Completeness +The `EncState::new()` method is described structurally but not fully implemented. The implementing agent MUST: +1. Provide complete `EncState::new()` with all FFI calls verified against `wl-screenrec/src/avhw.rs` +2. Implement the `AvHwDevCtx` → encoder `hw_frames_ctx` assignment via raw FFI +3. Implement the Vulkan `Pin>` self-referential pattern +4. Add `h264_metadata` BSF to the encoding pipeline for SPS/PPS injection +5. Verify VAAPI output at runtime by test-encoding one frame and inspecting NAL units + +### Task 9 (cap_*.rs) — Wayland Dispatch Implementations +The capture backend descriptions omit the `Dispatch` trait implementations (~400 lines total). The implementing agent MUST: +1. Provide complete `Dispatch` implementations for all Wayland protocol objects +2. For ext-image-copy: Dispatch for `ExtImageCopyCaptureSessionV1`, `ExtImageCopyCaptureFrameV1`, `ZwpLinuxDmabufFeedbackV1` +3. For wlr-screencopy: Dispatch for `ZwlrScreencopyFrameV1` +4. Dispatch for `WlOutput` and `XdgOutputManagerV1`/`XdgOutputV1` for output probing +5. Reference `wl-screenrec` for the complete pattern + +### Task Order Note +The plan implements Task 5-6 (transport/signaling) before Task 7-8 (FFmpeg). This is correct because `transport.rs` depends only on `nalu.rs`, NOT on `avhw.rs`. The channel-based architecture decouples the two pipelines — transport and encoding can be developed in parallel. diff --git a/docs/superpowers/specs/2026-04-03-wl-webrtc-architecture-design.md b/docs/superpowers/specs/2026-04-03-wl-webrtc-architecture-design.md new file mode 100644 index 0000000..d056524 --- /dev/null +++ b/docs/superpowers/specs/2026-04-03-wl-webrtc-architecture-design.md @@ -0,0 +1,619 @@ +# wl-webrtc Architecture Design + +**Date**: 2026-04-03 +**Status**: Draft +**Author**: Sisyphus (AI-assisted design) + +--- + +## 1. Overview + +### 1.1 Problem Statement + +Build a low-latency Wayland screen sharing server that captures the desktop via GPU, encodes with hardware acceleration (VAAPI/Vulkan), and streams to a browser for remote viewing and eventual remote control. + +### 1.2 Goals + +- **Glass-to-glass latency < 50ms** on LAN +- **GPU-accelerated pipeline**: capture + encode entirely on GPU, only encoded bitstream crosses to CPU +- **Browser-only client**: no native app installation required +- **Single binary deployment**: embedded web UI, no external dependencies +- **Linux Wayland only**: no cross-platform abstraction needed +- **Annex B mode**: encoder must emit in-band SPS/PPS with every keyframe via the `h264_metadata` bitstream filter (`repeat_sps=1` `repeat_pps=1`) — NOT `repeat_headers=1` (that option is libx264-only and does NOT exist for `h264_vaapi`) +- **Annex B streaming**: encoder outputs Annex B (start-code-prefixed) NAL units with SPS/PPS injected per-IDR via `h264_metadata` BSF (`repeat_sps=1` `repeat_pps=1`), browser decodes in Annex B mode via WebCodecs. Note: `repeat_headers=1` is a libx264-only option, NOT available for `h264_vaapi`. + +### 1.3 Non-Goals (Phase 1) + +- Multi-client support (Phase 2) +- Audio streaming (Phase 3) +- Remote input injection (Phase 2) +- Firefox support (Phase 3 — WebRTC fallback) +- Adaptive bitrate (Phase 3) + +### 1.4 Technology Stack + +| Component | Technology | Rationale | +|-----------|-----------|-----------| +| Screen capture | wayland-client + DMA-BUF | Zero-copy GPU capture via DMA-BUF | +| GPU encoding | FFmpeg (ffmpeg-next) VAAPI/Vulkan | H.264/HEVC hardware encoding | +| Transport | wtransport (WebTransport over HTTP/3) | Full HTTP/3 + WebTransport protocol, built on quinn + rustls | +| Browser decode | WebCodecs VideoDecoder | Direct decode control, no MSE buffering | +| Web UI | axum + rust-embed | Single binary, compile-time embedded static files | +| Event loop | mio | Proven with Wayland file descriptor callbacks | +| Async runtime | tokio | Required by wtransport, also powers axum | +| Sync/async bridge | async_channel | Both sync send() and async recv(), bridges mio → tokio naturally | + +### 1.5 Transport Decision: Why Not WebRTC + +WebRTC was evaluated and rejected as the primary transport for this use case: + +| Factor | WebRTC (webrtc-rs) | WebTransport + WebCodecs | +|--------|-------------------|-------------------------| +| Glass-to-glass latency | 30-110ms (unavoidable 20-60ms jitter buffer) | 12-38ms (no jitter buffer) | +| Rust ecosystem | webrtc-rs v0.20.0-alpha, mid-rewrite | wtransport production-grade, built on quinn | +| Protocol overhead | ICE/DTLS/SRTP/SDP — designed for P2P NAT traversal | QUIC TLS 1.3 — server-to-client, simpler | +| Decode control | Browser controls jitter buffer, cannot opt out | Application controls every frame decode | +| GPU data path | Sample { data: Bytes }, must copy to CPU | Same copy, but shorter pipeline | +| Browser support | All browsers | Chrome/Edge only (Firefox lacks WebCodecs) | + +**Transport library choice**: We use the `wtransport` crate (v0.7) instead of raw `quinn` + `h3`. The browser's `WebTransport` API requires a full HTTP/3 server with the WebTransport extension (RFC 9297). Raw QUIC is NOT sufficient — there is no browser API for raw QUIC connections. The `wtransport` crate provides the complete protocol stack (HTTP/3 + WebTransport) built on top of `quinn` 0.11 and `rustls` 0.23, with support for datagrams, unidirectional streams, and bidirectional streams. + +WebRTC will be added as a Phase 3 fallback for Firefox compatibility. + +--- + +## 2. Architecture + +### 2.1 Thread Model + +``` +┌─────────────────────────────────────────────────────────────┐ +│ wl-webrtc process │ +│ │ +│ Main Thread (mio event loop) │ +│ ┌──────────────────────────────────────────────────────┐ │ +│ │ Wayland event queue dispatch │ │ +│ │ Screen capture (DMA-BUF, zero-copy from compositor) │ │ +│ │ GPU encode (FFmpeg VAAPI/Vulkan, sync calls) │ │ +│ │ State machine transitions │ │ +│ │ FPS limiting │ │ +│ └──────────────────────┬───────────────────────────────┘ │ +│ │ │ +│ async_channel::bounded<16>(EncodedFrame) │ +│ │ │ +│ Tokio Runtime Thread Pool (2+ threads) │ +│ ┌──────────────────────▼───────────────────────────────┐ │ +│ │ wtransport WebTransport server │ │ +│ │ HTTP/3 + WebTransport session management │ │ +│ │ Frame distribution to connected clients │ │ +│ │ axum HTTP server (Web UI + control API) │ │ +│ │ rust-embed static file serving │ │ +│ └──────────────────────────────────────────────────────┘ │ +└─────────────────────────────────────────────────────────────┘ +``` + +**Design rationale**: + +- **Capture + encode on main thread**: GPU encoding is synchronous (3-8ms per frame at 30-60fps), doesn't block the mio event loop at these frame rates. This avoids cross-thread synchronization for the GPU pipeline. +- **wtransport on tokio**: wtransport is built on quinn and tokio. axum requires tokio. Both coexist naturally. Both the WebTransport server and the HTTP static file server share the same tokio runtime. +- **async_channel::bounded(16)**: Channel capacity of 16 frames provides ~260ms of buffer at 60fps — enough to absorb transport jitter without excessive latency. The sender uses `try_send()`: if the channel is full, the frame is dropped and logged. This is standard practice in real-time streaming — newer frames are always more valuable than older ones. `try_send()` returns `Err(TrySendError::Full(_))` on a full channel, which the main loop handles by discarding the frame. This avoids blocking the main mio event loop, which must remain responsive for Wayland event dispatch. **Do NOT use `send_blocking()`** on the mio thread — it would stall the capture pipeline if the transport consumer falls behind. + +### 2.2 Module Dependency Graph + +``` + ┌──────────┐ + │ main.rs │ entry point, CLI, orchestration + └──┬──┬─┬──┘ + │ │ │ + ┌────────────┘ │ └────────────┐ + ▼ ▼ ▼ + ┌──────────┐ ┌──────────┐ ┌────────────┐ + │ state.rs │ │ avhw.rs │ │ transport.rs│ + │ StateMachine │ HW ctx │ │ QUIC server │ + │ CaptureSource │ │ │ Sessions │ + └──┬───┬────┘ └────┬─────┘ └────────────┘ + │ │ │ + ┌─────┘ └──────┐ │ + ▼ ▼ ▼ +┌─────────┐ ┌────────────┐ ┌────────┐ +│cap_wlr_ │ │cap_ext_ │ │filter.rs│ +│screen │ │image_copy │ │ crop/ │ +│copy │ │ │ │ scale/ │ +└─────────┘ └────────────┘ │transpose│ + └────────┘ + ┌────────────┐ ┌──────────────┐ + │transform.rs│ │signaling.rs │ + │ coordinate │ │ axum + embed │ + │ transform │ │ Web UI serve │ + └────────────┘ └──────────────┘ + ┌────────────┐ + │fps_limit.rs│ + └────────────┘ +``` + +**Dependency layers** (bottom-up): + +1. `transform.rs`, `fps_limit.rs` — leaf modules, zero internal dependencies +2. `avhw.rs`, `filter.rs` — FFmpeg wrapper layer +3. `cap_wlr_screencopy.rs`, `cap_ext_image_copy.rs` — capture backends, depend on state + avhw +4. `state.rs` — state machine + CaptureSource trait +5. `transport.rs`, `signaling.rs` — network layer +6. `main.rs` — orchestration + +### 2.3 Project File Structure + +``` +wl-webrtc/ +├── Cargo.toml +├── README.md +├── src/ +│ ├── main.rs # ~300 lines — CLI, startup, orchestration +│ ├── state.rs # ~600 lines — State, EncConstructionStage, InFlightSurface +│ ├── avhw.rs # ~450 lines — FFmpeg HW device/frame contexts +│ ├── filter.rs # ~200 lines — FFmpeg video filter graph +│ ├── cap_wlr_screencopy.rs # ~170 lines — wlr-screencopy backend +│ ├── cap_ext_image_copy.rs # ~240 lines — ext-image-copy-capture backend +│ ├── transform.rs # ~220 lines — coordinate transforms +│ ├── fps_limit.rs # ~130 lines — VRR-aware frame rate limiter +│ ├── transport.rs # ~400 lines — QUIC/WebTransport server +│ ├── signaling.rs # ~200 lines — axum HTTP + WebSocket control +│ └── nalu.rs # ~150 lines — Annex B NAL unit splitting, framing protocol +├── static/ +│ ├── index.html # Web UI shell +│ ├── player.js # WebCodecs decoder + Canvas renderer +│ └── style.css # Minimal styling +└── protocols/ # Wayland protocol XML files +``` + +--- + +## 3. Data Flow + +### 3.1 Zero-Copy Capture Pipeline + +``` +GPU Frame Pool ─alloc()→ HW Surface + ↓ + av_hwframe_map → DMA-BUF fd + ↓ + zwp_linux_dmabuf → WlBuffer (fd shared) + ↓ + Compositor writes directly to GPU Surface + ↓ + FFmpeg VAAPI/Vulkan encode (GPU-internal) + ↓ + AVPacket.data (Annex B with 00 00 00 01 start codes) + ↓ ← GPU→CPU copy via vaMapBuffer (unavoidable) + Bytes::from(Vec) wrapper + ↓ + async_channel::bounded::send(EncodedFrame) // sync, non-blocking on main thread +``` + +### 3.2 Transport Pipeline + +``` +async_channel::bounded::recv(EncodedFrame) + ↓ + Frame byte-splitting at MTU boundaries (not NAL-aligned) + ↓ + ┌─ Keyframe → QUIC reliable stream (guaranteed delivery) + └─ Delta frame → QUIC datagram (unreliable, low latency) + ↓ + Quinn WebTransport send + ↓ + Browser WebTransport.receive() + ↓ + Frame reassembly (if fragmented) + ↓ + WebCodecs VideoDecoder.decode(EncodedVideoChunk) + ↓ + Canvas.drawImage(VideoFrame) +``` + +### 3.3 Latency Budget + +| Stage | Latency | Notes | +|-------|---------|-------| +| Wayland capture (KMS/dmabuf) | 1-3ms | Zero-copy from compositor | +| GPU encode (VAAPI H.264) | 3-8ms | Synchronous, main thread | +| vaMapBuffer CPU copy | <1ms | Unavoidable GPU→CPU | +| async_channel | <0.1ms | In-process | +| QUIC datagram (LAN) | 1-10ms | LAN transit, merged with network | +| WebCodecs decode | 2-5ms | Browser hardware decode | +| Canvas render | 1-2ms | requestAnimationFrame | +| **Total (LAN)** | **9-29ms** | Well under 50ms target (corrected: removed double-counted network transit) | + +### 3.4 EncodedFrame Structure + +```rust +#[derive(Clone)] +struct EncodedFrame { + data: Bytes, // Annex B NALUs with start codes + pts_us: i64, // Presentation timestamp (microseconds, for WebCodecs) + duration: Duration, // Frame duration for timestamp calculation + frame_type: FrameType, // Keyframe or Delta (matches transport framing) + width: u32, // Frame width (may differ from capture on ROI) + height: u32, // Frame height +} +``` + +**Timestamp convention**: `pts_us` is in **microseconds** (not nanoseconds), matching WebCodecs' `EncodedVideoChunk.timestamp` requirement. The server tracks a monotonic PTS starting from 0, incrementing by `1_000_000 / fps` per frame. + +--- + +## 4. State Machine + +### 4.1 EncConstructionStage + +``` + ┌──────────────────┐ + App start │ ProbingOutputs │ Discover Wayland outputs, + │ └────────┬─────────┘ collect geometry info + ▼ │ All outputs probed +┌───────────────┐ ▼ +│ ProbingOutputs├──→ ┌──────────────────┐ +└───────────────┘ │EverythingButFmt │ HW device ctx created, + └────────┬─────────┘ encoder initialized + │ negotiate_format() + ▼ + ┌───────────┐ + ┌─────→│ Streaming │──── Active capture + encode + transport + │ └─────┬─────┘ + │ │ Output disconnected + │ Format │ ┌──────────────┐ + │ changed │ │OutputWentAway│ Keep enc + transport, + │ │ └──────┬───────┘ drop capture objects + └────────────┘ │ Same output reconnects + ←───────────────────────┘ + + Intermediate transient exists at all transition arrows (mem::replace) +``` + +**Key design choice**: `Streaming` state holds both `EncState` (encoding pipeline) AND `TransportState` (active WebTransport sessions). On `OutputWentAway`, both are preserved — only capture objects are discarded. + +### 4.2 InFlightSurface + +``` +None → AllocQueued → Allocd(Frame) → CopyQueued { surface, drm_map, frame, buffer } → None +``` + +4-state enum with `assert!(matches!(...))` runtime guards. RAII cleanup on each state transition. Single-frame-in-flight constraint prevents buffer exhaustion. + +### 4.3 TransportSessionState (new) + +``` +┌───────────┐ connect ┌───────────┐ disconnect ┌───────────┐ +│ Listening │ ──────────────→ │ Active │ ──────────────→ │ Closed │ +│ (quinn │ │ (sending │ │ (cleanup) │ +│ endpoint)│ │ frames) │ │ │ +└───────────┘ └───────────┘ └───────────┘ +``` + +Multiple sessions can be `Active` simultaneously (Phase 2). Phase 1 supports exactly one. + +--- + +## 5. Design Patterns + +The architecture employs several established software design patterns for managing complexity: + +| # | Pattern | Usage in wl-webrtc | +|---|---------|-------------------| +| 1 | Strategy Trait + Generic State | `CaptureSource` trait with `CapWlrScreencopy` / `CapExtImageCopy` backends | +| 2 | Polymorphic Enum State Machine | `EncConstructionStage` — 5 variants with type-safe transitions | +| 3 | Type-Safe Frame Lifecycle | `InFlightSurface` — 4-state enum with runtime guards | +| 4 | Pin\ Self-Referential | Vulkan device context — for self-referential FFmpeg structs | +| 5 | Independent Thread Pipe | tokio runtime replaces mpsc audio thread; same atomic flag pattern | +| 6 | VRR-Aware Frame Rate Control | `FpsLimit` — one-frame-buffer delay for correct drop decisions | +| 7 | Generic Dispatch 3-Layer | Wayland protocol dispatch — generic event handling | +| 8 | Three-Stage Safe Construction | Incremental resource acquisition with partial state rollback | +| 9 | Hot-Plug Auto-Recovery | `OutputWentAway` — preserve encoder/transport, rebuild capture | +| 10 | Zero-Copy GPU Pipeline | DMA-BUF capture + GPU-internal encode, minimal CPU involvement | + +--- + +## 6. Transport Protocol Design + +### 6.1 WebTransport Connection Setup + +``` +Server generates self-signed TLS certificate (via wtransport built-in rcgen support) + → wtransport::Endpoint::server(server_config, addr) + → Browser: new WebTransport("https://server:PORT/wt") + → wtransport handles full HTTP/3 + WebTransport handshake internally + → Session established (datagrams + streams available) +``` + +**Transport library**: We use `wtransport` crate (v0.7) which provides a complete WebTransport-over-HTTP/3 server implementation built on top of `quinn` 0.11 and `rustls` 0.23. This handles all protocol details (HTTP/3 SETTINGS, CONNECT method with `:protocol = webtransport`, session management, datagram framing per RFC 9297). Raw `quinn` or `h3` would require building this protocol stack manually. + +### 6.2 Frame Framing Protocol + +QUIC datagrams have a practical MTU of ~1200 bytes. A 1080p H.264 frame is typically 10KB-200KB. Application-level framing: + +``` +Datagram format: +┌──────────┬──────────┬──────────┬──────────┬──────────┬─────────────┐ +│ type (1) │ frame_id │ pts_us │ seq_num │ total │ payload │ +│ │ (4 bytes)│ (8 bytes)│ (2 bytes)│ (2 bytes)│ (variable) │ +└──────────┴──────────┴──────────┴──────────┴──────────┴─────────────┘ + +type: + 0x01 = Keyframe fragment (sent via reliable stream, not datagram) + 0x02 = Delta frame fragment (sent via datagram) + 0x03 = Keyframe complete (small enough for single datagram) + 0x04 = Delta frame complete + 0x10 = Codec config (SPS/PPS for H.264, VPS/SPS/PPS for HEVC) + +pts_us: Presentation timestamp in microseconds (i64, big-endian). + Passed directly to WebCodecs EncodedVideoChunk.timestamp. + For fragmented frames, every fragment carries the same pts_us. +``` + +**Key design decisions**: +- **Keyframes via reliable WebTransport stream**: SPS/PPS + IDR data must not be lost. Use `session.open_uni().await` for reliable delivery. +- **Delta frames via datagram**: Loss-tolerant. If a delta frame is lost, the decoder waits for the next keyframe. This avoids accumulated corruption. +- **Frame reassembly in browser**: Buffer fragments by `frame_id`, reassemble when all `total` fragments arrive, decode complete frame. +- **Timestamp in microseconds**: The fragment header carries `pts_us: i64` (presentation timestamp in microseconds) so the browser can pass it directly to `EncodedVideoChunk.timestamp`. This is required by WebCodecs — a sequential frame_id counter is NOT a valid timestamp. + +### 6.3 Codec Configuration Exchange + +The encoder MUST be configured with the `h264_metadata` bitstream filter (`repeat_sps=1` `repeat_pps=1`) to guarantee SPS/PPS are injected into every IDR frame. Note: `repeat_headers=1` is a libx264-only option and does NOT exist for `h264_vaapi`. The browser configures the decoder in **Annex B mode** (no `description` at `configure()` time), and SPS/PPS arrive in-band with each keyframe. + +On session establishment, the server sends a codec configuration message over the reliable QUIC stream to inform the browser of the codec and dimensions: + +```json +{ + "type": "codec_config", + "codec": "avc1.42E01F", + "width": 1920, + "height": 1080, + "framerate": 60 +} +``` + +Browser uses this to configure `VideoDecoder` — without `description`, which activates Annex B mode: + +```javascript +decoder.configure({ + codec: config.codec, + codedWidth: config.width, + codedHeight: config.height, + // NO description — Annex B mode. SPS/PPS arrive in-band with each keyframe. +}); +``` + +**Why no AVCC description?** Per the WebCodecs AVC registration spec, providing `description` forces the decoder into AVC (length-prefixed) mode for ALL frames. Since our encoder outputs Annex B (start-code-prefixed), we must omit `description` and rely on in-band parameter sets guaranteed by the `h264_metadata` BSF (`repeat_sps=1` `repeat_pps=1`). Note: `repeat_headers=1` is a libx264-only option — it does NOT work with `h264_vaapi`. + +**Timestamp handling**: The `FragmentHeader` carries both a `frame_id` (u32) for reassembly ordering and `pts_us` (i64) — the presentation timestamp in microseconds. The browser uses `pts_us` directly as `EncodedVideoChunk.timestamp`. This is required by WebCodecs — a sequential frame_id counter is NOT a valid timestamp. Every fragment of a frame carries the same `pts_us` value so the browser can extract it from any fragment during reassembly. + +--- + +## 7. Browser-Side Design + +### 7.1 Web UI (static/index.html + player.js) + +Single-page application with minimal dependencies: + +``` +┌──────────────────────────────────────┐ +│ wl-webrtc │ +│ ┌──────────────────────────────┐ │ +│ │ │ │ +│ │ (video) │ │ +│ │ WebCodecs → drawImage │ │ +│ │ │ │ +│ └──────────────────────────────┘ │ +│ Status: Connected | Latency: 23ms │ +│ Resolution: 1920x1080 @ 60fps │ +│ [Fullscreen] [Disconnect] │ +└──────────────────────────────────────┘ +``` + +### 7.2 WebCodecs Decoder Pipeline + +**CRITICAL: Annex B mode only.** Per the [W3C AVC WebCodecs Registration](https://w3c.github.io/webcodecs/avc_codec_registration.html#videodecoderconfig-description), if `description` is provided at `configure()` time, ALL subsequent `EncodedVideoChunk` data must be in AVC format (4-byte length-prefixed). If `description` is **absent**, the bitstream is assumed to be in Annex B format (start-code-prefixed). Since our encoder outputs Annex B, we must NOT provide `description`. + +The encoder MUST be configured with the `h264_metadata` bitstream filter (`repeat_sps=1` `repeat_pps=1`) to guarantee SPS/PPS are injected into every IDR frame. Note: `repeat_headers=1` is a libx264-only option and does NOT exist for `h264_vaapi`. This enables the decoder to initialize from keyframe data alone. + +```javascript +// Simplified player.js flow +const transport = new WebTransport("https://server:PORT/wt"); +const decoder = new VideoDecoder({ + output: (frame) => { + ctx.drawImage(frame, 0, 0); + frame.close(); + }, + error: (e) => console.error(e), +}); + +// Configure WITHOUT description → Annex B mode. +// SPS/PPS are delivered in-band with each keyframe (via h264_metadata BSF repeat_sps=1 repeat_pps=1 on encoder). +decoder.configure({ + codec: "avc1.42E01F", + codedWidth: 1920, + codedHeight: 1080, + // NO description field — Annex B mode +}); + +// Receive frames +const reader = transport.datagrams.readable.getReader(); +while (true) { + const { value, done } = await reader.read(); + if (done) break; + const frame = reassembleFrame(value); + if (frame.complete) { + decoder.decode(new EncodedVideoChunk({ + type: frame.isKeyframe ? "key" : "delta", + timestamp: Number(frame.ptsUs), + data: frame.data, // Annex B — valid because no description was provided + })); + } +} +``` + +### 7.3 No Annex B → AVCC Conversion Needed + +Because we configure the decoder in Annex B mode (no `description`), no format conversion is needed on the browser side. The server sends raw Annex B NAL units with start codes (`00 00 00 01`), and the decoder accepts them directly. + +The encoder MUST be configured with the `h264_metadata` bitstream filter (`repeat_sps=1` `repeat_pps=1`) to guarantee SPS/PPS are included in every IDR frame. Note: `repeat_headers=1` (and `-flags2 +repeat_headers`) are libx264-only options — they do NOT work with `h264_vaapi`. The BSF approach is encoder-agnostic and works with all FFmpeg hardware encoders. This ensures the decoder can re-initialize after any keyframe, even if it missed earlier configuration data. + +--- + +## 8. Error Handling & Recovery + +### 8.1 Display Hot-Plug + +1. `wl_registry.global_remove` → set `output_went_away` flag +2. `on_copy_fail()` detects flag → transition to `OutputWentAway` +3. Preserve: encoder context, transport sessions, WebRTC connections +4. Discard: Wayland protocol objects (invalidated) +5. Wait for same-name output ("DP-1") to reappear +6. Create new `CaptureSource`, reuse old encoder, continue streaming + +### 8.2 Network Disconnection + +- QUIC handles keepalive and retransmission internally +- Client page refresh → new WebTransport session → server auto-starts sending current frame stream +- Server is stateless per session — no recovery needed, just reconnect + +### 8.3 Dynamic Format Change + +Capture format changes (resolution, rotation): +1. Rebuild: `frames_rgb`, `video_filter`, `enc_video`, `frames_yuv` +2. Preserve: `hw_device_ctx`, `transport_state` +3. Send new codec configuration to browser via reliable stream +4. Browser reconfigures `VideoDecoder` with new SPS/PPS and dimensions + +### 8.4 Frame Loss Handling + +- Lost delta frame → decoder continues, minor artifact until next keyframe +- Lost keyframe → decoder cannot continue → request keyframe from server via reliable stream +- Server receives keyframe request → sets next input frame to `AV_PICTURE_TYPE_I` + +### 8.5 Graceful Shutdown + +Shutdown is triggered by SIGINT/SIGTERM via `signal-hook` + `mio` integration: + +1. Main loop sets `running = false` flag → stops queuing new captures +2. Wait for in-flight frame to complete (drain `InFlightSurface`) +3. Flush encoder (`avcodec_flush_buffers`) → drain remaining packets +4. Send final frames through channel +5. Drop `frame_tx` sender → signals EOF to transport +6. Transport server drains pending frames, sends GOAWAY to clients +7. `tokio::runtime::shutdown_background()` terminates async tasks +8. Drop Wayland protocol objects (compositor handles cleanup) +9. FFmpeg contexts freed via `Drop` implementations + +**Key concern**: Do NOT use blocking `send_blocking()` on the main thread — use `try_send()` so the main loop never stalls during shutdown. If the channel is full, the frame is dropped (acceptable during shutdown). + +**NOTE**: wayland-client 0.31 uses `Connection::connect_to_env()` and `GlobalList` instead of the old 0.29 API (`Display::connect_to_env()` / `GlobalManager::new()`). See plan Task 11 for correct API usage. + +### 8.6 First Keyframe Delivery + +When a new WebTransport session is established, the client needs a keyframe before it can decode any delta frames. Two strategies: + +1. **Force IDR on connect**: Set `AV_PICTURE_TYPE_I` on the next encoded frame when a new session is detected +2. **Buffer last keyframe**: Store the most recent keyframe in `TransportServer`, resend to new clients + +Phase 1 uses strategy 1 (force IDR) for simplicity. The transport server sets a `needs_keyframe: bool` flag on new sessions, which the encode loop checks. + +--- + +## 9. Dependencies + +```toml +[dependencies] +# Wayland screen capture +wayland-client = "0.31" +wayland-protocols = { version = "0.32", features = ["client", "unstable", "staging"] } +wayland-protocols-wlr = { version = "0.3", features = ["client"] } +drm-fourcc = "2" + +# GPU encoding +ffmpeg-next = "8" + +# WebTransport (HTTP/3 + WebTransport protocol, built on quinn + rustls) +wtransport = { version = "0.7", features = ["self-signed"] } + +# Web UI +axum = { version = "0.8", features = ["ws"] } +tower-http = { version = "0.6", features = ["cors"] } +rust-embed = { version = "8", features = ["mime-guess"] } + +# Async runtime +tokio = { version = "1", features = ["full"] } + +# Sync/async bridge (sync send() on mio thread, async recv() on tokio) +async-channel = "2" + +# Event loop +mio = "1" + +# Utilities +clap = { version = "4", features = ["derive"] } +tracing = "0.1" +tracing-subscriber = "0.3" +anyhow = "1" +bytes = "1" +serde = { version = "1", features = ["derive"] } +serde_json = "1" +signal-hook = { version = "0.3", features = ["iterator"] } +base64 = "0.22" +mime_guess = "2" +``` + +**Encoder configuration note**: The VAAPI H.264 encoder MUST be configured with the `h264_metadata` bitstream filter (`repeat_sps=1` `repeat_pps=1`) to guarantee SPS/PPS parameter sets are emitted in-band with every IDR frame. This is required for WebCodecs Annex B decode mode on the browser side. **Important**: `repeat_headers=1` and `-flags2 +repeat_headers` are libx264-only options — they do NOT work with `h264_vaapi`. The BSF approach is encoder-agnostic and works with all FFmpeg hardware encoders. + +--- + +## 10. Implementation Phases + +### Phase 1 — MVP: Screen → Browser Streaming + +| # | Module | Description | Estimated Effort | +|---|--------|-------------|------------------| +| 1 | `main.rs` | CLI args, startup sequence | Small | +| 2 | `cap_*.rs` | Implement capture backends (wlr-screencopy + ext-image-copy) | Medium | +| 3 | `avhw.rs` | Implement FFmpeg HW device/frame context management | Medium | +| 4 | `filter.rs` | Implement GPU video filter graph | Small | +| 5 | `transform.rs` | Implement coordinate transforms for Wayland outputs | Small | +| 6 | `fps_limit.rs` | Implement VRR-aware frame rate limiter | Small | +| 7 | `state.rs` | State machine adapted for transport | Medium | +| 8 | `transport.rs` | QUIC server + frame distribution | Large (new code) | +| 9 | `nalu.rs` | Annex B framing protocol | Small (new code) | +| 10 | `signaling.rs` | axum server + static files | Small (new code) | +| 11 | `static/*` | Browser Web UI + WebCodecs player | Medium (new code) | + +**Deliverable**: Run `wl-webrtc`, open `https://localhost:PORT` in Chrome, see live screen at <50ms latency. + +### Phase 2 — Remote Input + Stability + +| # | Feature | Description | +|---|---------|-------------| +| 12 | Remote input | Browser mouse/keyboard → wlr-virtual-pointer/virtual-keyboard | +| 13 | Hot-plug recovery | Display disconnect/reconnect | +| 14 | Dynamic format | Resolution/rotation change handling | +| 15 | Multi-client | Multiple simultaneous browser viewers | + +### Phase 3 — Optimization + Compatibility + +| # | Feature | Description | +|---|---------|-------------| +| 16 | Adaptive bitrate | Network-aware VAAPI bit_rate adjustment | +| 17 | Audio pipeline | Synchronous audio capture + encoding + transport | +| 18 | WebRTC fallback | webrtc-rs path for Firefox compatibility | +| 19 | Performance dashboard | Real-time stats in Web UI | + +--- + +## 11. Open Questions + +1. **ffmpeg-next vs direct VAAPI bindings**: ffmpeg-next adds FFI overhead but provides mature encoding pipeline. Direct vaapi-dmabuf bindings would be more Rust-native but much more implementation work. **Decision: ffmpeg-next for Phase 1, evaluate direct bindings in Phase 3.** NOTE: `ffmpeg-next` safe API does NOT wrap hardware contexts (`AVBufferRef`, `AVHWFramesContext`). Use raw `ffmpeg_next::ffi` directly for all HW context operations — see `wl-screenrec/src/avhw.rs` for the reference pattern. + +2. **Frame fragmentation strategy**: Current design fragments large frames across QUIC datagrams at byte boundaries (not NAL-aligned). The framing protocol reassembles by `frame_id`, so a lost fragment invalidates the entire frame. Alternative: send all frames via reliable QUIC streams and accept slightly higher latency. **Decision: Start with datagrams for delta frames, measure latency, evaluate.** + +3. **Self-signed certificate UX**: Browser will show SSL warning. Options: (a) accept for LAN, (b) guide user to trust CA, (c) use HTTP/2 prior knowledge. **Decision: Accept for Phase 1, add CA trust guide in Phase 2.** + +4. **HEVC vs H.264 default**: H.264 has universal browser support. HEVC has better compression but spotty browser support. **Decision: H.264 default, HEVC as option flag.** + +5. **WebCodecs bitstream format**: **Decision: Annex B mode (no `description` at configure time).** SPS/PPS are guaranteed in-band via the `h264_metadata` BSF (`repeat_sps=1` `repeat_pps=1`). **Important**: The `repeat_headers=1` encoder option is libx264-only — it does NOT work with `h264_vaapi`. The BSF approach is encoder-agnostic and works with all FFmpeg hardware encoders. Per the W3C AVC WebCodecs Registration, providing `description` forces AVC (length-prefixed) mode for ALL subsequent frames. Since our encoder outputs Annex B, we must omit `description`. diff --git a/shell.nix b/shell.nix new file mode 100644 index 0000000..ba824e7 --- /dev/null +++ b/shell.nix @@ -0,0 +1,18 @@ +{ pkgs ? import {} }: + +pkgs.mkShell { + buildInputs = with pkgs; [ + pkg-config + rustc + cargo + clang + ffmpeg_6-full + wayland + wayland-protocols + libdrm + mesa + libva + ]; + + LIBCLANG_PATH = "${pkgs.llvmPackages.libclang.lib}/lib"; +} diff --git a/src/args.rs b/src/args.rs new file mode 100644 index 0000000..e3d2992 --- /dev/null +++ b/src/args.rs @@ -0,0 +1,45 @@ +use clap::Parser; + +#[derive(Parser, Debug, Clone)] +#[command(name = "wl-webrtc", about = "Wayland screen capture and encoding tool")] +pub struct Args { + /// Output file path (e.g., output.mp4, output.mkv) + #[arg(short, long)] + pub output: String, + + /// Wayland output name to capture + #[arg(long)] + pub output_name: Option, + + /// Target frames per second + #[arg(long, default_value_t = 30)] + pub fps: u32, + + /// Video codec (h264 only for MVP) + #[arg(long, default_value = "h264")] + pub codec: String, + + /// Hardware acceleration method (vaapi only for MVP) + #[arg(long, default_value = "vaapi")] + pub hw_accel: String, + + /// DRM render device path (e.g., /dev/dri/renderD128) + #[arg(long)] + pub drm_device: Option, + + /// Target bitrate in bits per second + #[arg(long)] + pub bitrate: Option, + + /// Group of Pictures (GOP) size + #[arg(long)] + pub gop_size: Option, + + /// Enable verbose logging + #[arg(short, long)] + pub verbose: bool, + + /// Port for WebTransport server (Phase 2, unused in MVP) + #[arg(long, default_value_t = 0)] + pub port: u16, +} diff --git a/src/avhw.rs b/src/avhw.rs new file mode 100644 index 0000000..efc565a --- /dev/null +++ b/src/avhw.rs @@ -0,0 +1,672 @@ +use std::ffi::CString; +use std::path::Path; +use std::ptr; + +use anyhow::{bail, Result}; +use ffmpeg_next as ff; +use ffmpeg_next::ffi as ffi; +use ffmpeg_next::packet::Mut as _; + +// --------------------------------------------------------------------------- +// BSF FFI — ffmpeg-sys-next does not expose the BSF API; declare manually. +// Linked from libavcodec (always present when avcodec feature is enabled). +// --------------------------------------------------------------------------- + +#[repr(C)] +pub struct AVBitStreamFilter { + _opaque: [u8; 0], +} + +#[repr(C)] +pub struct AVBSFContext { + av_class: *const ffi::AVClass, + filter: *const AVBitStreamFilter, + priv_data: *mut libc::c_void, + par_in: *mut ffi::AVCodecParameters, + par_out: *mut ffi::AVCodecParameters, + time_base_in: ffi::AVRational, + time_base_out: ffi::AVRational, +} + +extern "C" { + pub fn av_bsf_get_by_name(name: *const libc::c_char) -> *const AVBitStreamFilter; + pub fn av_bsf_alloc( + filter: *const AVBitStreamFilter, + ctx: *mut *mut AVBSFContext, + ) -> libc::c_int; + pub fn av_bsf_init(ctx: *mut AVBSFContext) -> libc::c_int; + pub fn av_bsf_send_packet(ctx: *mut AVBSFContext, pkt: *mut ffi::AVPacket) -> libc::c_int; + pub fn av_bsf_receive_packet(ctx: *mut AVBSFContext, pkt: *mut ffi::AVPacket) -> libc::c_int; + pub fn av_bsf_free(ctx: *mut *mut AVBSFContext); +} + +// --------------------------------------------------------------------------- +// AvHwDevCtx +// --------------------------------------------------------------------------- + +pub struct AvHwDevCtx { + ptr: *mut ffi::AVBufferRef, +} + +unsafe impl Send for AvHwDevCtx {} + +impl AvHwDevCtx { + pub fn new_vaapi(drm_device: &Path) -> Result { + let device_cstr = CString::new(drm_device.to_str().unwrap())?; + let mut p: *mut ffi::AVBufferRef = ptr::null_mut(); + let ret = unsafe { + ffi::av_hwdevice_ctx_create( + &mut p, + ffi::AVHWDeviceType::AV_HWDEVICE_TYPE_VAAPI, + device_cstr.as_ptr(), + ptr::null_mut(), + 0, + ) + }; + if ret < 0 { + bail!( + "Failed to create VAAPI device context from {}: error {ret}", + drm_device.display() + ); + } + Ok(Self { ptr: p }) + } + + pub fn as_ptr(&self) -> *mut ffi::AVBufferRef { + self.ptr + } + + pub fn ref_clone(&self) -> *mut ffi::AVBufferRef { + // SAFETY: av_buffer_ref atomically increments refcount and returns a new ref. + unsafe { ffi::av_buffer_ref(self.ptr) } + } +} + +impl Drop for AvHwDevCtx { + fn drop(&mut self) { + if !self.ptr.is_null() { + // SAFETY: av_buffer_unref decrements refcount; frees the buffer when it hits zero. + unsafe { ffi::av_buffer_unref(&mut self.ptr) }; + } + } +} + +// --------------------------------------------------------------------------- +// AvHwFrameCtx +// --------------------------------------------------------------------------- + +pub struct AvHwFrameCtx { + ptr: *mut ffi::AVBufferRef, +} + +unsafe impl Send for AvHwFrameCtx {} + +impl AvHwFrameCtx { + fn new_inner( + hw_dev: &AvHwDevCtx, + w: u32, + h: u32, + sw_fmt: ff::format::Pixel, + ) -> Result { + let mut p = unsafe { ffi::av_hwframe_ctx_alloc(hw_dev.as_ptr()) }; + if p.is_null() { + bail!("av_hwframe_ctx_alloc returned null"); + } + // SAFETY: p is a valid AVBufferRef from av_hwframe_ctx_alloc. + // Its .data field points to an AVHWFramesContext that we must configure. + unsafe { + let fc = (*p).data as *mut ffi::AVHWFramesContext; + (*fc).format = ff::format::Pixel::VAAPI.into(); + (*fc).sw_format = sw_fmt.into(); + (*fc).width = w as i32; + (*fc).height = h as i32; + (*fc).initial_pool_size = 4; + } + let ret = unsafe { ffi::av_hwframe_ctx_init(p) }; + if ret < 0 { + // SAFETY: p is valid but init failed; clean up. + unsafe { ffi::av_buffer_unref(&mut p) }; + bail!("av_hwframe_ctx_init failed: error {ret}"); + } + Ok(Self { ptr: p }) + } + + pub fn for_capture( + hw_dev: &AvHwDevCtx, + w: u32, + h: u32, + sw_fmt: ff::format::Pixel, + ) -> Result { + Self::new_inner(hw_dev, w, h, sw_fmt) + } + + pub fn for_encode( + hw_dev: &AvHwDevCtx, + w: u32, + h: u32, + sw_fmt: ff::format::Pixel, + ) -> Result { + Self::new_inner(hw_dev, w, h, sw_fmt) + } + + pub fn as_ptr(&self) -> *mut ffi::AVBufferRef { + self.ptr + } + + pub fn ref_clone(&self) -> *mut ffi::AVBufferRef { + // SAFETY: av_buffer_ref atomically increments refcount and returns a new ref. + unsafe { ffi::av_buffer_ref(self.ptr) } + } +} + +impl Drop for AvHwFrameCtx { + fn drop(&mut self) { + if !self.ptr.is_null() { + // SAFETY: av_buffer_unref decrements refcount; frees when zero. + unsafe { ffi::av_buffer_unref(&mut self.ptr) }; + } + } +} + +// --------------------------------------------------------------------------- +// EncState +// --------------------------------------------------------------------------- + +pub struct EncState { + enc_video: ff::codec::encoder::video::Video, + bsf_ctx: *mut AVBSFContext, + frames_rgb: AvHwFrameCtx, + frames_yuv: AvHwFrameCtx, + video_filter: ff::filter::Graph, + hw_device_ctx: AvHwDevCtx, + octx: ff::format::context::Output, + starting_timestamp: Option, + frames_written: bool, +} + +unsafe impl Send for EncState {} + +#[allow(clippy::too_many_arguments)] +impl EncState { + pub fn new( + drm_device: &Path, + output_path: &Path, + width: u32, + height: u32, + bitrate: u64, + gop_size: u32, + fps: u32, + ) -> Result { + // 1. VAAPI device + let hw_device_ctx = AvHwDevCtx::new_vaapi(drm_device)?; + + // 2. Frame contexts (capture=XRGB/RGBZ, encode=NV12) + let frames_rgb = AvHwFrameCtx::for_capture( + &hw_device_ctx, + width, + height, + ff::format::Pixel::RGBZ, + )?; + let frames_yuv = AvHwFrameCtx::for_encode( + &hw_device_ctx, + width, + height, + ff::format::Pixel::NV12, + )?; + + // 3. Find h264_vaapi encoder + let codec = ff::encoder::find_by_name("h264_vaapi") + .ok_or_else(|| anyhow::anyhow!("h264_vaapi encoder not found"))?; + + let mut enc = { + let ctx = ff::codec::Context::new_with_codec(codec); + ctx.encoder().video()? + }; + + enc.set_width(width); + enc.set_height(height); + enc.set_format(ff::format::Pixel::VAAPI); + enc.set_bit_rate(bitrate as usize); + enc.set_gop(gop_size); + enc.set_time_base(ff::Rational::new(1, fps as i32)); + enc.set_max_b_frames(0); + + // SAFETY: AV_CODEC_FLAG_GLOBAL_HEADER must be set BEFORE opening the encoder. + // It triggers SPS/PPS extradata generation needed by the muxer for + // Annex B to AVCC conversion. + unsafe { + (*enc.as_mut_ptr()).flags |= ffi::AV_CODEC_FLAG_GLOBAL_HEADER as i32; + } + // SAFETY: Assign hw device and frames ctx to the encoder. + unsafe { + (*enc.as_mut_ptr()).hw_device_ctx = hw_device_ctx.ref_clone(); + (*enc.as_mut_ptr()).hw_frames_ctx = frames_yuv.ref_clone(); + } + + // 4. Open encoder. Video::open() returns Encoder(Video); .0 extracts the Video. + let opened = enc.open().map_err(|e| { + anyhow::anyhow!("Failed to open h264_vaapi encoder: {e}") + })?; + let enc_video = opened.0; + + // --- BSF init (after encoder open, before filter graph) --- + // SAFETY: av_bsf_get_by_name returns a pointer to a static filter definition. + let bsf_name = CString::new("h264_metadata").unwrap(); + let filter = unsafe { av_bsf_get_by_name(bsf_name.as_ptr()) }; + if filter.is_null() { + bail!("h264_metadata BSF not found in FFmpeg build"); + } + + let mut bsf_ctx: *mut AVBSFContext = ptr::null_mut(); + let ret = unsafe { av_bsf_alloc(filter, &mut bsf_ctx) }; + if ret < 0 { + bail!("av_bsf_alloc failed: error {ret}"); + } + + // SAFETY: avcodec_parameters_from_context copies FROM AVCodecContext TO AVCodecParameters. + let ret = unsafe { + ffi::avcodec_parameters_from_context((*bsf_ctx).par_in, enc_video.as_ptr()) + }; + if ret < 0 { + // SAFETY: bsf_ctx was allocated but not yet initialized — safe to free + unsafe { av_bsf_free(&mut bsf_ctx) }; + bail!("avcodec_parameters_from_context for BSF failed: error {ret}"); + } + + // SAFETY: time_base_in is a plain AVRational field, safe to write + unsafe { + (*bsf_ctx).time_base_in = (*enc_video.as_ptr()).time_base; + } + + // Set repeat_sps=1 + let key_sps = CString::new("repeat_sps").unwrap(); + let val_one = CString::new("1").unwrap(); + let ret = unsafe { + ffi::av_opt_set((*bsf_ctx).priv_data, key_sps.as_ptr(), val_one.as_ptr(), 0) + }; + if ret < 0 { + // SAFETY: bsf_ctx allocated but not fully initialized — safe to free + unsafe { av_bsf_free(&mut bsf_ctx) }; + bail!("av_opt_set repeat_sps failed: error {ret}"); + } + + // Set repeat_pps=1 + let key_pps = CString::new("repeat_pps").unwrap(); + let ret = unsafe { + ffi::av_opt_set((*bsf_ctx).priv_data, key_pps.as_ptr(), val_one.as_ptr(), 0) + }; + if ret < 0 { + // SAFETY: bsf_ctx allocated, repeat_sps set but not init'd — safe to free + unsafe { av_bsf_free(&mut bsf_ctx) }; + bail!("av_opt_set repeat_pps failed: error {ret}"); + } + + // Initialize BSF + let ret = unsafe { av_bsf_init(bsf_ctx) }; + if ret < 0 { + // SAFETY: bsf_ctx allocated, params set but init failed — safe to free + unsafe { av_bsf_free(&mut bsf_ctx) }; + bail!("av_bsf_init failed: error {ret}"); + } + + // 5. Filter graph (inline) + let video_filter = + build_filter_graph(&hw_device_ctx, &frames_rgb, width, height, fps)?; + + // 6. Muxer setup (strict order) + let output_cstr = CString::new(output_path.to_str().unwrap())?; + let mut fmt_ctx_ptr: *mut ffi::AVFormatContext = ptr::null_mut(); + + // SAFETY: avformat_alloc_output_context2 creates format context from + // the file extension. Does NOT open the file. + let ret = unsafe { + ffi::avformat_alloc_output_context2( + &mut fmt_ctx_ptr, + ptr::null_mut(), + ptr::null(), + output_cstr.as_ptr(), + ) + }; + if ret < 0 || fmt_ctx_ptr.is_null() { + bail!("Failed to allocate output format context: error {ret}"); + } + + // SAFETY: avformat_query_codec checks codec+format compatibility. + let codec_id = unsafe { (*enc_video.as_ptr()).codec_id }; + let oformat = unsafe { (*fmt_ctx_ptr).oformat }; + let compat = unsafe { + ffi::avformat_query_codec(oformat, codec_id, ffi::FF_COMPLIANCE_NORMAL as i32) + }; + if compat < 0 { + bail!("H.264 codec not supported by output container format"); + } + + // SAFETY: avformat_new_stream creates a new stream in the format context. + let stream_ptr = unsafe { ffi::avformat_new_stream(fmt_ctx_ptr, ptr::null()) }; + if stream_ptr.is_null() { + bail!("Failed to create new stream in output context"); + } + + // SAFETY: avcodec_parameters_from_context copies encoder params + extradata. + let ret = unsafe { + ffi::avcodec_parameters_from_context((*stream_ptr).codecpar, enc_video.as_ptr()) + }; + if ret < 0 { + bail!("Failed to copy encoder parameters to stream: error {ret}"); + } + + // SAFETY: Copy encoder time_base to stream. + unsafe { + (*stream_ptr).time_base = (*enc_video.as_ptr()).time_base; + } + + // SAFETY: avio_open opens the output file for writing. + let ret = unsafe { + ffi::avio_open( + &mut (*fmt_ctx_ptr).pb, + output_cstr.as_ptr(), + ffi::AVIO_FLAG_WRITE, + ) + }; + if ret < 0 { + bail!( + "Failed to open output file '{}': error {ret}", + output_path.display() + ); + } + + // SAFETY: avformat_write_header writes the container header. + let ret = unsafe { ffi::avformat_write_header(fmt_ctx_ptr, ptr::null_mut()) }; + if ret < 0 { + bail!("Failed to write output header: error {ret}"); + } + + // SAFETY: We created fmt_ctx_ptr above and it's valid. + let octx = unsafe { ff::format::context::Output::wrap(fmt_ctx_ptr) }; + + Ok(Self { + enc_video, + bsf_ctx, + frames_rgb, + frames_yuv, + video_filter, + hw_device_ctx, + octx, + starting_timestamp: None, + frames_written: false, + }) + } + + pub fn frames_rgb(&self) -> &AvHwFrameCtx { + &self.frames_rgb + } + + pub fn encode_frame(&mut self, hw_frame: &ff::frame::Video) -> Result<()> { + let mut filter_src_ctx = self.video_filter.get("in").unwrap(); + let mut filter_src = filter_src_ctx.source(); + let mut filter_sink_ctx = self.video_filter.get("out").unwrap(); + let mut filter_sink = filter_sink_ctx.sink(); + + // SAFETY: hw_frame is a valid VAAPI hardware frame from capture. + filter_src.add(hw_frame).map_err(|e| { + anyhow::anyhow!("Filter source add failed: {e}") + })?; + + loop { + let mut filtered = ff::frame::Video::empty(); + match filter_sink.frame(&mut filtered) { + Ok(()) => { + if filtered.pts().is_none() { + filtered.set_pts(hw_frame.pts()); + } + } + Err(ff::Error::Other { errno }) if errno == ffi::EAGAIN => break, + Err(e) => bail!("Filter sink get frame failed: {e}"), + } + + let pts = filtered.pts().unwrap_or(0); + if self.starting_timestamp.is_none() { + self.starting_timestamp = Some(pts); + } + let start_ts = self.starting_timestamp.unwrap(); + + // SAFETY: avcodec_send_frame sends a valid NV12 VAAPI surface to the encoder. + let ret = unsafe { + ffi::avcodec_send_frame(self.enc_video.as_mut_ptr(), filtered.as_ptr()) + }; + if ret < 0 { + bail!("avcodec_send_frame failed: error {ret}"); + } + self.drain_encoder(start_ts)?; + } + + Ok(()) + } + + pub fn flush(&mut self) -> Result<()> { + // Flush filter graph + let mut filter_src_ctx = self.video_filter.get("in").unwrap(); + let mut filter_src = filter_src_ctx.source(); + let _ = filter_src.flush(); + + // Drain filter + let mut filter_sink_ctx = self.video_filter.get("out").unwrap(); + let mut filter_sink = filter_sink_ctx.sink(); + loop { + let mut filtered = ff::frame::Video::empty(); + match filter_sink.frame(&mut filtered) { + Ok(()) => { + let start_ts = self.starting_timestamp.unwrap_or(0); + let ret = unsafe { + ffi::avcodec_send_frame(self.enc_video.as_mut_ptr(), filtered.as_ptr()) + }; + if ret < 0 { + bail!("avcodec_send_frame failed during flush: error {ret}"); + } + self.drain_encoder(start_ts)?; + } + Err(_) => break, + } + } + + // SAFETY: Sending null frame signals end of stream. + unsafe { + ffi::avcodec_send_frame(self.enc_video.as_mut_ptr(), ptr::null()); + } + + let start_ts = self.starting_timestamp.unwrap_or(0); + self.drain_encoder(start_ts)?; + + // SAFETY: Sending null packet signals end-of-stream to BSF + unsafe { av_bsf_send_packet(self.bsf_ctx, ptr::null_mut()) }; + loop { + let mut bsf_pkt = ff::Packet::empty(); + let ret = unsafe { + av_bsf_receive_packet(self.bsf_ctx, bsf_pkt.as_mut_ptr()) + }; + if ret < 0 { break; } + let enc_tb = self.enc_video.time_base(); + let stream_tb = unsafe { + let streams = (*self.octx.as_ptr()).streams; + let st = *streams.add(0); + ff::Rational::from((*st).time_base) + }; + bsf_pkt.rescale_ts(enc_tb, stream_tb); + if let Some(pts) = bsf_pkt.pts() { + bsf_pkt.set_pts(Some(pts - start_ts)); + } + if let Some(dts) = bsf_pkt.dts() { + bsf_pkt.set_dts(Some(dts - start_ts)); + } + bsf_pkt.set_stream(0); + bsf_pkt.write_interleaved(&mut self.octx).map_err(|e| { + anyhow::anyhow!("Failed to write BSF flush packet: {e}") + })?; + self.frames_written = true; + } + + // Write trailer only if at least one frame was encoded. + if self.frames_written { + self.octx.write_trailer().map_err(|e| { + anyhow::anyhow!("Failed to write trailer: {e}") + })?; + } + + Ok(()) + } + + fn drain_encoder(&mut self, start_ts: i64) -> Result<()> { + let stream_index: i32 = 0; + loop { + let mut pkt = ff::Packet::empty(); + // SAFETY: avcodec_receive_packet retrieves an encoded packet. + let ret = unsafe { + ffi::avcodec_receive_packet(self.enc_video.as_mut_ptr(), pkt.as_mut_ptr()) + }; + if ret < 0 { + if ret == ffi::AVERROR(ffi::EAGAIN) || ret == ffi::AVERROR_EOF { + break; + } + bail!("avcodec_receive_packet failed: error {ret}"); + } + + // SAFETY: av_bsf_send_packet sends the encoded packet through the BSF filter. + // On success, the BSF takes ownership of the packet data (via av_packet_move_ref). + let ret = unsafe { av_bsf_send_packet(self.bsf_ctx, pkt.as_mut_ptr()) }; + if ret == ffi::AVERROR(ffi::EAGAIN) { + // BSF buffer full — break and retry next drain cycle + break; + } + if ret < 0 { + bail!("av_bsf_send_packet failed: error {ret}"); + } + + // Drain all BSF output packets + loop { + let mut bsf_pkt = ff::Packet::empty(); + // SAFETY: av_bsf_receive_packet retrieves a BSF-processed packet. + let ret = unsafe { + av_bsf_receive_packet(self.bsf_ctx, bsf_pkt.as_mut_ptr()) + }; + if ret == ffi::AVERROR(ffi::EAGAIN) { + break; // No more output yet + } + if ret == ffi::AVERROR_EOF { + break; // BSF drained + } + if ret < 0 { + bail!("av_bsf_receive_packet failed: error {ret}"); + } + + // Rescale and offset on BSF output packet (NOT original pkt) + let enc_tb = self.enc_video.time_base(); + let stream_tb = unsafe { + let streams = (*self.octx.as_ptr()).streams; + let st = *streams.add(0); + ff::Rational::from((*st).time_base) + }; + bsf_pkt.rescale_ts(enc_tb, stream_tb); + + if let Some(pts) = bsf_pkt.pts() { + bsf_pkt.set_pts(Some(pts - start_ts)); + } + if let Some(dts) = bsf_pkt.dts() { + bsf_pkt.set_dts(Some(dts - start_ts)); + } + + bsf_pkt.set_stream(stream_index as usize); + bsf_pkt.write_interleaved(&mut self.octx).map_err(|e| { + anyhow::anyhow!("Failed to write packet: {e}") + })?; + + self.frames_written = true; + } + } + Ok(()) + } +} + +impl Drop for EncState { + fn drop(&mut self) { + // SAFETY: av_bsf_free releases the BSF context and all associated resources. + // It handles null safely (returns immediately if *pctx is null). + if !self.bsf_ctx.is_null() { + unsafe { av_bsf_free(&mut self.bsf_ctx) }; + } + } +} + +// --------------------------------------------------------------------------- +// Filter graph (inline) +// --------------------------------------------------------------------------- + +fn build_filter_graph( + hw_dev: &AvHwDevCtx, + frames_rgb: &AvHwFrameCtx, + width: u32, + height: u32, + fps: u32, +) -> Result { + let mut graph = ff::filter::Graph::new(); + + let buffersrc = ff::filter::find("buffer") + .ok_or_else(|| anyhow::anyhow!("filter 'buffer' not found"))?; + let buffersink = ff::filter::find("buffersink") + .ok_or_else(|| anyhow::anyhow!("filter 'buffersink' not found"))?; + let format_filter = ff::filter::find("format") + .ok_or_else(|| anyhow::anyhow!("filter 'format' not found"))?; + let scale_vaapi = ff::filter::find("scale_vaapi") + .ok_or_else(|| anyhow::anyhow!("filter 'scale_vaapi' not found"))?; + + // buffersrc — use AVBufferSrcParameters to set hw_frames_ctx properly + let args = format!( + "video_size={}x{}:pix_fmt={}:time_base=1/{fps}:pixel_aspect=1/1", + width, + height, + Into::::into(ff::format::Pixel::VAAPI) as i32, + ); + let mut src_ctx = graph.add(&buffersrc, "in", &args)?; + + // SAFETY: av_buffersrc_parameters_alloc allocates params for the buffersrc. + let par = unsafe { ffi::av_buffersrc_parameters_alloc() }; + if par.is_null() { + bail!("av_buffersrc_parameters_alloc returned null"); + } + // SAFETY: Set hw_frames_ctx on the buffersrc parameters, then apply. + unsafe { + (*par).format = Into::::into(ff::format::Pixel::VAAPI) as i32; + (*par).width = width as i32; + (*par).height = height as i32; + (*par).time_base = ffi::AVRational { num: 1, den: fps as i32 }; + (*par).hw_frames_ctx = frames_rgb.ref_clone(); + let ret = ffi::av_buffersrc_parameters_set(src_ctx.as_mut_ptr(), par); + ffi::av_freep(par as *mut _ as *mut _); + if ret < 0 { + bail!("av_buffersrc_parameters_set failed: error {ret}"); + } + } + + // format filter: negotiate pixel format to NV12 + let mut fmt_ctx = graph.add(&format_filter, "fmt", "pix_fmts=nv12")?; + + // scale_vaapi: hardware scaling and colourspace conversion + let mut scale_ctx = graph.add(&scale_vaapi, "scale", &format!("{width}:{height}"))?; + // SAFETY: scale_vaapi needs hw_device_ctx for VAAPI device access. + unsafe { + (*scale_ctx.as_mut_ptr()).hw_device_ctx = hw_dev.ref_clone(); + } + + // buffersink + let mut sink_ctx = graph.add(&buffersink, "out", "")?; + + // Link: src -> format -> scale -> sink + src_ctx.link(0, &mut fmt_ctx, 0); + fmt_ctx.link(0, &mut scale_ctx, 0); + scale_ctx.link(0, &mut sink_ctx, 0); + + graph.validate().map_err(|e| { + anyhow::anyhow!("Filter graph validation failed: {e}") + })?; + + Ok(graph) +} diff --git a/src/cap_wlr_screencopy.rs b/src/cap_wlr_screencopy.rs new file mode 100644 index 0000000..32aa3c1 --- /dev/null +++ b/src/cap_wlr_screencopy.rs @@ -0,0 +1,64 @@ +use anyhow::Result; +use wayland_client::globals::GlobalList; +use wayland_client::protocol::wl_buffer::WlBuffer; +use wayland_client::protocol::wl_output::WlOutput; +use wayland_client::QueueHandle; +use wayland_protocols_wlr::screencopy::v1::client::zwlr_screencopy_frame_v1::ZwlrScreencopyFrameV1; + +use crate::state::{CaptureSource, OutputInfo, State}; + +/// wlr-screencopy capture backend. +/// +/// Holds the current in-flight frame protocol object. The +/// `ZwlrScreencopyManagerV1` is stored separately in +/// `State::EverythingButFmt` because binding it requires a `Dispatch` +/// impl that lives in state.rs (T6b). +pub struct CapWlrScreencopy { + /// The active frame object for the current capture cycle. + /// Set by Dispatch impls after `manager.capture_output()`, cleared + /// by `on_done_with_frame()`. + pub current_frame: Option, +} + +impl CaptureSource for CapWlrScreencopy { + /// Unit type: wlr-screencopy is fully asynchronous — `alloc_frame()` + /// always returns `None`. The frame object is created by Dispatch + /// impls calling `manager.capture_output()`, not by this method. + type Frame = (); + + fn new( + _gm: &GlobalList, + _output: &WlOutput, + _output_info: &OutputInfo, + _qh: &QueueHandle>, + ) -> Result { + // Manager binding happens in state.rs during the ProbingOutputs → + // EverythingButFmt stage transition (T6b). It requires a Dispatch + // impl that doesn't exist yet, so we cannot call gm.bind() here. + Ok(Self { + current_frame: None, + }) + } + + fn alloc_frame(&mut self) -> Option { + // wlr-screencopy is asynchronous: the Dispatch impl creates a new + // ZwlrScreencopyFrameV1 which triggers the buffer allocation flow + // (buffer event → negotiate format → create DMA-BUF). This method + // always returns None. + None + } + + fn queue_copy(&mut self, buffer: &WlBuffer, _qh: &QueueHandle>) { + if let Some(frame) = &self.current_frame { + frame.copy(buffer); + } else { + tracing::warn!("queue_copy: no current wlr-screencopy frame"); + } + } + + fn on_done_with_frame(&mut self, _frame: Self::Frame) { + if let Some(frame) = self.current_frame.take() { + frame.destroy(); + } + } +} diff --git a/src/fps_limit.rs b/src/fps_limit.rs new file mode 100644 index 0000000..a617227 --- /dev/null +++ b/src/fps_limit.rs @@ -0,0 +1,77 @@ +use std::time::{Duration, Instant}; + +pub struct FpsLimit { + on_deck: Option<(T, Instant)>, + min_interval: Duration, +} + +impl FpsLimit { + pub fn new(fps: u32) -> Self { + Self { + on_deck: None, + min_interval: Duration::from_secs_f64(1.0 / fps as f64), + } + } + + /// Feed a new frame. Returns: + /// - Some(previous_frame) if enough time elapsed since previous frame + /// - None if frame is buffered (first frame) or previous is dropped (too close) + pub fn on_new_frame(&mut self, frame: T, timestamp: Instant) -> Option { + let old = self.on_deck.replace((frame, timestamp)); + match old { + None => None, // First frame — buffer it + Some((old_frame, old_ts)) => { + if timestamp.duration_since(old_ts) >= self.min_interval { + Some(old_frame) // Enough time — output previous + } else { + None // Too close — discard previous, keep new + } + } + } + } + + /// Flush the last buffered frame at end of stream + pub fn flush(&mut self) -> Option { + self.on_deck.take().map(|(frame, _ts)| frame) + } +} + +#[cfg(test)] +mod tests { + use super::*; + + #[test] + fn first_frame_is_buffered() { + let mut limiter: FpsLimit = FpsLimit::new(30); + let now = Instant::now(); + let result = limiter.on_new_frame(1u32, now); + assert!(result.is_none()); + } + + #[test] + fn frames_too_close_drops_old() { + let mut limiter: FpsLimit = FpsLimit::new(30); + let now = Instant::now(); + limiter.on_new_frame(1, now); + let result = limiter.on_new_frame(2, now + Duration::from_millis(1)); + assert!(result.is_none()); + } + + #[test] + fn frames_far_enough_output_old() { + let mut limiter: FpsLimit = FpsLimit::new(30); + let now = Instant::now(); + limiter.on_new_frame(1, now); + let result = limiter.on_new_frame(2, now + Duration::from_millis(40)); + assert_eq!(result, Some(1)); + } + + #[test] + fn flush_returns_last_buffered() { + let mut limiter: FpsLimit = FpsLimit::new(30); + let now = Instant::now(); + limiter.on_new_frame(1, now); + assert_eq!(limiter.flush(), Some(1)); + assert_eq!(limiter.flush(), None); + } +} diff --git a/src/main.rs b/src/main.rs new file mode 100644 index 0000000..ad57520 --- /dev/null +++ b/src/main.rs @@ -0,0 +1,148 @@ +use std::os::unix::io::AsRawFd; + +use anyhow::Result; +use clap::Parser; +use mio::unix::SourceFd; +use mio::{Events, Interest, Poll, Token}; +use wayland_client::globals::registry_queue_init; +use wayland_client::Connection; + +mod args; +mod avhw; +mod cap_wlr_screencopy; +mod fps_limit; +mod state; +mod transform; + +use crate::args::Args; +use crate::cap_wlr_screencopy::CapWlrScreencopy; +use crate::state::State; + +const TOKEN_WAYLAND: Token = Token(0); +const TOKEN_QUIT: Token = Token(1); + +fn main() -> Result<()> { + let args = Args::parse(); + + tracing_subscriber::fmt() + .with_max_level(if args.verbose { + tracing::Level::DEBUG + } else { + tracing::Level::INFO + }) + .init(); + + tracing::info!("wl-webrtc starting"); + tracing::debug!("Args: {:?}", args); + + if args.codec != "h264" { + anyhow::bail!("HEVC not supported in MVP. Use --codec h264"); + } + + // Connect to Wayland compositor + let conn = Connection::connect_to_env()?; + let (gm, mut queue) = registry_queue_init::>(&conn)?; + + // Get the Wayland socket fd for mio polling. + // Use prepare_read() once to obtain the fd, then immediately drop the guard. + let wayland_fd = { + let guard = queue + .prepare_read() + .ok_or_else(|| anyhow::anyhow!("Failed to prepare Wayland read"))?; + guard.connection_fd().as_raw_fd() + }; + + // Create initial state + let qhandle = queue.handle(); + let mut state = State::new(gm, args, qhandle); + + // Dispatch initial round to bind all globals (screencopy manager, dmabuf, outputs) + queue.blocking_dispatch(&mut state)?; + + // Set up mio event loop + let mut poll = Poll::new()?; + let mut events = Events::with_capacity(8); + + // Register Wayland fd with mio + poll.registry().register( + &mut SourceFd(&wayland_fd), + TOKEN_WAYLAND, + Interest::READABLE, + )?; + + // Register signal handler + let mut signals = signal_hook_mio::v1_0::Signals::new(&[ + signal_hook::consts::SIGINT, + signal_hook::consts::SIGTERM, + ])?; + poll.registry() + .register(&mut signals, TOKEN_QUIT, Interest::READABLE)?; + + tracing::info!("Event loop started"); + + // Main event loop + let mut running = true; + while running { + // Wayland read pattern: + // 1. prepare_read() marks intent to read (also flushes outgoing) + // 2. poll() waits for data on Wayland fd or signals + // 3. If Wayland readable: read() consumes the guard, then dispatch_pending() + // 4. Dropping the guard without read() cancels the prepared read + + let read_guard = queue.prepare_read(); + + poll.poll(&mut events, Some(std::time::Duration::from_millis(100))) + .unwrap_or_else(|e| { + tracing::error!("poll failed: {e}"); + running = false; + }); + + for event in &events { + if event.token() == TOKEN_QUIT { + tracing::info!("Received quit signal"); + running = false; + } + } + + if events.iter().any(|e| e.token() == TOKEN_WAYLAND) { + if let Some(guard) = read_guard { + match guard.read() { + Ok(_) => { + queue.dispatch_pending(&mut state)?; + } + Err(e) => { + tracing::error!("Wayland read error: {e}"); + running = false; + } + } + } + } + + // If we didn't consume the read guard (no WAYLAND event), it drops here + // and cancels the prepared read. That's fine — we'll retry next iteration. + + // After dispatch, try to start a new capture frame if we're in Streaming + // with no in-flight surface. + state.queue_alloc_frame(); + + // Check for fatal errors from the state machine + if state.errored { + tracing::error!("Fatal error in state machine, exiting"); + running = false; + } + + // Flush outgoing Wayland messages + conn.flush()?; + } + + // Clean shutdown: flush encoder and write MP4 trailer + tracing::info!("Shutting down, flushing encoder..."); + if let crate::state::EncConstructionStage::Streaming { enc, .. } = &mut state.stage { + if let Err(e) = enc.flush() { + tracing::error!("Failed to flush encoder: {e}"); + } + } + + tracing::info!("Done"); + Ok(()) +} diff --git a/src/state.rs b/src/state.rs new file mode 100644 index 0000000..9211559 --- /dev/null +++ b/src/state.rs @@ -0,0 +1,996 @@ +use std::mem; +use std::os::fd::{AsFd, OwnedFd}; +use std::os::unix::io::FromRawFd; +use std::path::{Path, PathBuf}; +use std::time::Instant; + +use anyhow::Result; +use wayland_client::globals::{GlobalList, GlobalListContents}; +use wayland_client::protocol::wl_buffer::WlBuffer; +use wayland_client::protocol::wl_output::WlOutput; +use wayland_client::protocol::wl_registry::WlRegistry; +use wayland_client::{Dispatch, Proxy, QueueHandle}; +use wayland_protocols::wp::linux_dmabuf::zv1::client::zwp_linux_buffer_params_v1::{ + Event as BufferParamsEvent, Flags as BufferParamsFlags, ZwpLinuxBufferParamsV1, +}; +use wayland_protocols::wp::linux_dmabuf::zv1::client::zwp_linux_dmabuf_feedback_v1::{ + Event as DmabufFeedbackEvent, ZwpLinuxDmabufFeedbackV1, +}; +use wayland_protocols::wp::linux_dmabuf::zv1::client::zwp_linux_dmabuf_v1::{ + Event as DmabufEvent, ZwpLinuxDmabufV1, +}; +use wayland_protocols::xdg::xdg_output::zv1::client::zxdg_output_manager_v1::ZxdgOutputManagerV1; +use wayland_protocols::xdg::xdg_output::zv1::client::zxdg_output_v1::{ + Event as XdgOutputEvent, ZxdgOutputV1, +}; +use wayland_protocols_wlr::screencopy::v1::client::zwlr_screencopy_frame_v1::{ + Event as ScreencopyFrameEvent, ZwlrScreencopyFrameV1, +}; +use wayland_protocols_wlr::screencopy::v1::client::zwlr_screencopy_manager_v1::ZwlrScreencopyManagerV1; + +use ffmpeg_next as ff; +use ffmpeg_next::ffi as ffi; + +use crate::args::Args; +use crate::avhw::{AvHwDevCtx, EncState}; +use crate::cap_wlr_screencopy::CapWlrScreencopy; +use crate::fps_limit::FpsLimit; +use crate::transform::Transform; + +// --------------------------------------------------------------------------- +// CaptureSource trait +// --------------------------------------------------------------------------- + +/// Screen capture backend trait. +pub trait CaptureSource: Sized + 'static { + type Frame: Send; + + fn new( + gm: &GlobalList, + output: &WlOutput, + output_info: &OutputInfo, + qh: &QueueHandle>, + ) -> Result; + + fn alloc_frame(&mut self) -> Option; + + fn queue_copy(&mut self, buffer: &WlBuffer, qh: &QueueHandle>); + + fn on_done_with_frame(&mut self, frame: Self::Frame); +} + +// --------------------------------------------------------------------------- +// Output info types +// --------------------------------------------------------------------------- + +pub struct OutputInfo { + pub name: String, + pub transform: Transform, + pub physical_size: (i32, i32), + pub logical_position: (i32, i32), +} + +pub struct PartialOutputInfo { + pub name: Option, + pub transform: Option, + pub physical_size: Option<(i32, i32)>, + pub logical_position: Option<(i32, i32)>, + // Pixel dimensions from Mode event — preparatory for Phase 2 resolution logic + pub mode_size: Option<(i32, i32)>, + pub done_count: u32, +} + +impl Default for PartialOutputInfo { + fn default() -> Self { + Self { + name: None, + transform: None, + physical_size: None, + logical_position: None, + mode_size: None, + done_count: 0, + } + } +} + +/// User data for XdgOutput dispatch to identify which WlOutput it belongs to. +pub struct OutputId(pub u32); + +// --------------------------------------------------------------------------- +// EncConstructionStage +// --------------------------------------------------------------------------- + +pub enum EncConstructionStage { + ProbingOutputs { + outputs: Vec, + bound_outputs: Vec, + output_names: Vec, + screencopy_manager: Option, + dmabuf: Option, + dmabuf_feedback: Option, + xdg_output_manager: Option, + }, + EverythingButFmt { + output_info: OutputInfo, + output: WlOutput, + hw_device_ctx: AvHwDevCtx, + cap: S, + screencopy_manager: ZwlrScreencopyManagerV1, + dmabuf: ZwpLinuxDmabufV1, + }, + Streaming { + output_info: OutputInfo, + output: WlOutput, + enc: EncState, + cap: S, + screencopy_manager: ZwlrScreencopyManagerV1, + dmabuf: ZwpLinuxDmabufV1, + }, + Intermediate, +} + +// --------------------------------------------------------------------------- +// InFlightSurface +// --------------------------------------------------------------------------- + +pub enum InFlightSurface { + None, + AllocQueued, + Allocd(S::Frame), + CopyQueued { + surface: ff::frame::Video, + drm_map: ff::ffi::AVDRMFrameDescriptor, + frame: S::Frame, + buffer: WlBuffer, + }, +} + +// --------------------------------------------------------------------------- +// State +// --------------------------------------------------------------------------- + +pub struct State { + pub stage: EncConstructionStage, + pub in_flight_surface: InFlightSurface, + pub starting_timestamp: Option, + pub args: Args, + pub errored: bool, + pub gm: GlobalList, + pub fps_limit: FpsLimit, + pub qhandle: QueueHandle>, + pub drm_device: Option, + pub drm_device_from_compositor: Option, +} + +// --------------------------------------------------------------------------- +// Helpers +// --------------------------------------------------------------------------- + +/// Scan /dev/dri for the first available DRM render node (renderD*). +fn find_drm_render_node() -> Option { + std::fs::read_dir("/dev/dri").ok()? + .filter_map(|e| e.ok()) + .filter(|e| { + e.file_name() + .to_str() + .map(|s| s.starts_with("renderD")) + .unwrap_or(false) + }) + .filter_map(|e| { + let path = e.path(); + std::fs::metadata(&path).ok()?; + Some(path) + }) + .min_by_key(|e| e.to_path_buf()) +} + +impl State { + fn resolve_drm_path(&self) -> PathBuf { + self.drm_device + .clone() + .or_else(|| self.drm_device_from_compositor.clone()) + .or_else(find_drm_render_node) + .unwrap_or_else(|| PathBuf::from("/dev/dri/renderD128")) + } +} + +// --------------------------------------------------------------------------- +// State methods +// --------------------------------------------------------------------------- + +impl State { + pub fn new(gm: GlobalList, args: Args, qhandle: QueueHandle>) -> Self { + let fps = args.fps; + let drm_device = args.drm_device.as_ref().map(PathBuf::from); + Self { + stage: EncConstructionStage::ProbingOutputs { + outputs: Vec::new(), + bound_outputs: Vec::new(), + output_names: Vec::new(), + screencopy_manager: None, + dmabuf: None, + dmabuf_feedback: None, + xdg_output_manager: None, + }, + in_flight_surface: InFlightSurface::None, + starting_timestamp: None, + fps_limit: FpsLimit::new(fps), + args, + errored: false, + gm, + qhandle, + drm_device, + drm_device_from_compositor: None, + } + } + + pub fn queue_alloc_frame(&mut self) + where + State: Dispatch, + { + let (manager, output) = match &self.stage { + EncConstructionStage::Streaming { + screencopy_manager, + output, + .. + } => (screencopy_manager.clone(), output.clone()), + EncConstructionStage::EverythingButFmt { + screencopy_manager, + output, + .. + } => (screencopy_manager.clone(), output.clone()), + _ => return, + }; + match &self.in_flight_surface { + InFlightSurface::None => {} + _ => return, + } + let _frame_proxy = manager.capture_output(1, &output, &self.qhandle, ()); + self.in_flight_surface = InFlightSurface::AllocQueued; + } + + pub fn on_frame_allocd(&mut self, frame: S::Frame, format: u32, width: u32, height: u32) { + let (frames_rgb_ctx, dmabuf, cap) = match &mut self.stage { + EncConstructionStage::Streaming { + output_info: _, + output: _, + enc, + dmabuf, + cap, + screencopy_manager: _, + } => (enc.frames_rgb().as_ptr(), dmabuf, cap), + _ => { + tracing::warn!("on_frame_allocd: not in Streaming stage"); + return; + } + }; + + let mut surface = ff::frame::Video::empty(); + // SAFETY: frames_rgb_ctx is a valid AVHWFramesContext pointer; surface + // is a freshly allocated empty Video frame. + let ret = unsafe { + ffi::av_hwframe_get_buffer(frames_rgb_ctx, surface.as_mut_ptr(), 0) + }; + if ret < 0 { + tracing::error!("av_hwframe_get_buffer failed: error {}", ret); + self.errored = true; + return; + } + + let mut map_frame = ff::frame::Video::empty(); + // SAFETY: Setting format to DRM_PRIME and calling av_hwframe_map creates + // a mapped view of the GPU surface with DMA-BUF file descriptors. + unsafe { + (*map_frame.as_mut_ptr()).format = + ffi::AVPixelFormat::AV_PIX_FMT_DRM_PRIME as i32; + } + let ret = unsafe { ffi::av_hwframe_map(map_frame.as_mut_ptr(), surface.as_ptr(), 0) }; + if ret < 0 { + tracing::error!("av_hwframe_map failed: error {}", ret); + self.errored = true; + return; + } + + // SAFETY: After av_hwframe_map with DRM_PRIME format, data[0] points to + // a valid AVDRMFrameDescriptor. + let desc: ff::ffi::AVDRMFrameDescriptor = unsafe { + let desc_ptr = + (*map_frame.as_ptr()).data[0] as *const ff::ffi::AVDRMFrameDescriptor; + std::ptr::read(desc_ptr) + }; + + let params = dmabuf.create_params(&self.qhandle, ()); + + for layer_idx in 0..desc.nb_layers as usize { + let layer = &desc.layers[layer_idx]; + for p in 0..layer.nb_planes as usize { + let plane = &layer.planes[p]; + let obj = &desc.objects[plane.object_index as usize]; + let mod_hi = (obj.format_modifier >> 32) as u32; + let mod_lo = (obj.format_modifier & 0xFFFF_FFFF) as u32; + // SAFETY: obj.fd is a valid DMA-BUF fd. We dup because params.add() + // takes ownership of the fd, and the original fd is owned by map_frame. + let fd_dup = unsafe { libc::dup(obj.fd) }; + if fd_dup < 0 { + tracing::error!("failed to dup dma-buf fd"); + self.errored = true; + return; + } + // SAFETY: fd_dup is valid freshly-duped fd. + let fd_owned = unsafe { OwnedFd::from_raw_fd(fd_dup) }; + params.add( + fd_owned.as_fd(), + p as u32, + plane.offset as u32, + plane.pitch as u32, + mod_hi, + mod_lo, + ); + } + } + + let wl_buffer = params.create_immed( + width as i32, + height as i32, + format, + BufferParamsFlags::empty(), + &self.qhandle, + (), + ); + self.in_flight_surface = InFlightSurface::CopyQueued { + surface, + drm_map: desc, + frame, + buffer: wl_buffer, + }; + let buffer_ref = match &self.in_flight_surface { + InFlightSurface::CopyQueued { buffer, .. } => buffer, + _ => unreachable!("just set to CopyQueued"), + }; + cap.queue_copy(buffer_ref, &self.qhandle); + } + + pub fn on_copy_complete(&mut self, tv_sec: u64, tv_usec: u32) + where + S::Frame: Default, + { + let (mut surface, _drm_map, frame, buffer) = match mem::replace( + &mut self.in_flight_surface, + InFlightSurface::None, + ) { + InFlightSurface::CopyQueued { + surface, + drm_map, + frame, + buffer, + } => (surface, drm_map, frame, buffer), + other => { + tracing::warn!("on_copy_complete: unexpected state"); + self.in_flight_surface = other; + return; + } + }; + let pts = (tv_sec as i64) * 1_000_000 + (tv_usec as i64); + surface.set_pts(Some(pts)); + drop(buffer); + let cap = match &mut self.stage { + EncConstructionStage::Streaming { cap, .. } => cap, + _ => { + tracing::warn!("on_copy_complete: not in Streaming stage"); + return; + } + }; + cap.on_done_with_frame(frame); + let enc = match &mut self.stage { + EncConstructionStage::Streaming { enc, .. } => enc, + _ => unreachable!("already checked Streaming above"), + }; + let should_encode = self.fps_limit.on_new_frame(S::Frame::default(), Instant::now()).is_some(); + if should_encode { + if let Err(e) = enc.encode_frame(&surface) { + tracing::error!("encode_frame failed: {}", e); + self.errored = true; + } + } + } + + pub fn on_copy_fail(&mut self) { + tracing::error!("compositor copy failed"); + self.errored = true; + } + + pub fn negotiate_format(&mut self, format: u32, width: u32, height: u32) { + let stage_data = match mem::replace(&mut self.stage, EncConstructionStage::Intermediate) { + EncConstructionStage::EverythingButFmt { + output_info, + output, + hw_device_ctx: _hw_device_ctx, + cap, + screencopy_manager, + dmabuf, + } => (output_info, output, cap, screencopy_manager, dmabuf), + other => { + tracing::warn!("negotiate_format: not in EverythingButFmt stage"); + self.stage = other; + return; + } + }; + let (output_info, output, cap, screencopy_manager, dmabuf) = stage_data; + let drm_path = self.resolve_drm_path(); + let bitrate = self.args.bitrate.unwrap_or_else(|| { + let fps = self.args.fps as u64; + 2 * (width as u64) * (height as u64) * fps / 100 + }); + let gop_size = self.args.gop_size.unwrap_or(self.args.fps); + let fps = self.args.fps; + let enc = match EncState::new( + &drm_path, + Path::new(&self.args.output), + width, + height, + bitrate, + gop_size, + fps, + ) { + Ok(enc) => enc, + Err(e) => { + tracing::error!("EncState::new failed: {}", e); + self.errored = true; + return; + } + }; + tracing::info!( + "Encoder initialized: {}x{} format={} bitrate={}", + width, height, format, bitrate + ); + self.stage = EncConstructionStage::Streaming { + output_info, + output, + enc, + cap, + screencopy_manager, + dmabuf, + }; + } + + fn try_finalize_output(&mut self, _idx: usize) -> bool { + let (target_idx, output_count) = match &self.stage { + EncConstructionStage::ProbingOutputs { outputs, .. } => { + let output_count = outputs.len(); + let idx = if let Some(ref name) = self.args.output_name { + let pos = outputs.iter().position(|o| o.name.as_deref() == Some(name.as_str())); + match pos { + Some(i) => Some(i), + None => { + let all_probed = outputs.iter().all(|o| o.done_count >= 2); + if all_probed { + let available: Vec<&str> = outputs.iter() + .filter_map(|o| o.name.as_deref()) + .collect(); + tracing::error!("Output '{}' not found. Available outputs: {:?}", name, available); + self.errored = true; + } + None + } + } + } else if outputs.iter().all(|o| o.done_count >= 2) { + if outputs.is_empty() { + return false; + } + Some(0) + } else { + None + }; + match idx { + Some(i) => { + let info = &outputs[i]; + if info.done_count < 2 + || info.name.is_none() + || info.transform.is_none() + || info.physical_size.is_none() + || info.logical_position.is_none() + { + return false; + } + (i, output_count) + } + None => return false, + } + } + _ => return false, + }; + + let probing = match mem::replace(&mut self.stage, EncConstructionStage::Intermediate) { + s @ EncConstructionStage::ProbingOutputs { .. } => s, + other => { + self.stage = other; + return false; + } + }; + + let ( + outputs, + bound_outputs, + _output_names, + screencopy_manager, + dmabuf, + dmabuf_feedback, + _xdg_output_manager, + ) = match probing { + EncConstructionStage::ProbingOutputs { + outputs, + bound_outputs, + output_names, + screencopy_manager, + dmabuf, + dmabuf_feedback, + xdg_output_manager, + } => ( + outputs, + bound_outputs, + output_names, + screencopy_manager, + dmabuf, + dmabuf_feedback, + xdg_output_manager, + ), + _ => unreachable!(), + }; + // Destroy feedback object — prevents server-side resource leak + if let Some(feedback) = dmabuf_feedback { + feedback.destroy(); + } + + let info = &outputs[target_idx]; + let output_info = OutputInfo { + name: info.name.clone().unwrap(), + transform: info.transform.unwrap(), + physical_size: info.physical_size.unwrap(), + logical_position: info.logical_position.unwrap(), + }; + let output = bound_outputs[target_idx].clone(); + + let screencopy_manager = match screencopy_manager { + Some(m) => m, + None => { + tracing::error!("No screencopy manager bound"); + self.errored = true; + return false; + } + }; + let dmabuf = match dmabuf { + Some(d) => d, + None => { + tracing::error!("No dmabuf manager bound"); + self.errored = true; + return false; + } + }; + + let drm_path = self.resolve_drm_path(); + + let hw_device_ctx = match AvHwDevCtx::new_vaapi(&drm_path) { + Ok(ctx) => ctx, + Err(e) => { + tracing::error!("Failed to create VAAPI device: {}", e); + self.errored = true; + return false; + } + }; + + let cap = match S::new(&self.gm, &output, &output_info, &self.qhandle) { + Ok(c) => c, + Err(e) => { + tracing::error!("Failed to create capture source: {}", e); + self.errored = true; + return false; + } + }; + + tracing::info!("Selected output: {}", output_info.name); + if self.args.output_name.is_none() && output_count > 1 { + tracing::warn!("Multiple outputs found, using '{}'. Use --output-name to select.", output_info.name); + } + self.stage = EncConstructionStage::EverythingButFmt { + output_info, + output, + hw_device_ctx, + cap, + screencopy_manager, + dmabuf, + }; + + true + } +} + +// --------------------------------------------------------------------------- +// Dispatch +// --------------------------------------------------------------------------- + +impl Dispatch for State { + fn event( + state: &mut Self, + registry: &WlRegistry, + event: wayland_client::protocol::wl_registry::Event, + _data: &GlobalListContents, + _conn: &wayland_client::Connection, + qhandle: &QueueHandle>, + ) { + use wayland_client::protocol::wl_registry::Event as RegistryEvent; + + match event { + RegistryEvent::Global { name, interface, version } => { + match interface.as_str() { + "zwlr_screencopy_manager_v1" => { + let v = version.min(3); + tracing::debug!("Binding zwlr_screencopy_manager_v1 v{v} (name={name})"); + let mgr: ZwlrScreencopyManagerV1 = registry.bind(name, v, qhandle, ()); + if let EncConstructionStage::ProbingOutputs { screencopy_manager, .. } = &mut state.stage { + *screencopy_manager = Some(mgr); + } + } + "zwp_linux_dmabuf_v1" => { + let v = version.min(4); + tracing::debug!("Binding zwp_linux_dmabuf_v1 v{v} (name={name})"); + let proxy: ZwpLinuxDmabufV1 = registry.bind(name, v, qhandle, ()); + if let EncConstructionStage::ProbingOutputs { dmabuf, dmabuf_feedback, .. } = &mut state.stage { + *dmabuf = Some(proxy.clone()); + if v >= 4 { + let feedback = proxy.get_default_feedback(qhandle, ()); + *dmabuf_feedback = Some(feedback); + } + } + } + "wl_output" => { + let v = version.min(4); + tracing::debug!("Binding wl_output v{v} (name={name})"); + let output: WlOutput = registry.bind(name, v, qhandle, ()); + if let EncConstructionStage::ProbingOutputs { + outputs, bound_outputs, output_names, xdg_output_manager, .. + } = &mut state.stage { + outputs.push(PartialOutputInfo::default()); + bound_outputs.push(output.clone()); + output_names.push(name); + if let Some(xdg_mgr) = xdg_output_manager { + let output_id = OutputId(name); + xdg_mgr.get_xdg_output(&output, qhandle, output_id); + } + } + } + "zxdg_output_manager_v1" => { + let v = version.min(3); + tracing::debug!("Binding zxdg_output_manager_v1 v{v} (name={name})"); + let xdg_mgr: ZxdgOutputManagerV1 = registry.bind(name, v, qhandle, ()); + if let EncConstructionStage::ProbingOutputs { + bound_outputs, xdg_output_manager, output_names, .. + } = &mut state.stage { + for (i, output) in bound_outputs.iter().enumerate() { + let oname = output_names.get(i).copied().unwrap_or(0); + let output_id = OutputId(oname); + xdg_mgr.get_xdg_output(output, qhandle, output_id); + } + *xdg_output_manager = Some(xdg_mgr); + } + } + _ => {} + } + } + RegistryEvent::GlobalRemove { name } => { + tracing::debug!("Global removed: name={name}"); + } + _ => {} + } + } +} + +// --------------------------------------------------------------------------- +// Dispatch +// --------------------------------------------------------------------------- + +impl Dispatch for State { + fn event( + state: &mut Self, + _proxy: &WlOutput, + event: wayland_client::protocol::wl_output::Event, + _data: &(), + _conn: &wayland_client::Connection, + _qhandle: &QueueHandle>, + ) { + use wayland_client::protocol::wl_output::Event as OutputEvent; + use wayland_client::protocol::wl_output::Mode as WlMode; + use wayland_client::protocol::wl_output::Transform as WlTransform; + + let idx = match &mut state.stage { + EncConstructionStage::ProbingOutputs { outputs, .. } => { + outputs.len().saturating_sub(1) + } + _ => return, + }; + + match event { + OutputEvent::Geometry { transform, physical_width, physical_height, .. } => { + let t = match transform { + wayland_client::WEnum::Value(WlTransform::Normal) => Transform::Normal, + wayland_client::WEnum::Value(WlTransform::_90) => Transform::Normal90, + wayland_client::WEnum::Value(WlTransform::_180) => Transform::Normal180, + wayland_client::WEnum::Value(WlTransform::_270) => Transform::Normal270, + wayland_client::WEnum::Value(WlTransform::Flipped) => Transform::Flipped, + wayland_client::WEnum::Value(WlTransform::Flipped90) => Transform::Flipped90, + wayland_client::WEnum::Value(WlTransform::Flipped180) => Transform::Flipped180, + wayland_client::WEnum::Value(WlTransform::Flipped270) => Transform::Flipped270, + _ => Transform::Normal, + }; + if let EncConstructionStage::ProbingOutputs { outputs, .. } = &mut state.stage { + if let Some(info) = outputs.get_mut(idx) { + info.transform = Some(t); + info.physical_size = Some((physical_width, physical_height)); + } + } + } + OutputEvent::Mode { width, height, flags, .. } => { + let is_current = matches!(flags, wayland_client::WEnum::Value(WlMode::Current)); + if is_current { + if let EncConstructionStage::ProbingOutputs { outputs, .. } = &mut state.stage { + if let Some(info) = outputs.get_mut(idx) { + info.mode_size = Some((width, height)); + } + } + } + } + OutputEvent::Done => { + if let EncConstructionStage::ProbingOutputs { outputs, .. } = &mut state.stage { + if let Some(info) = outputs.get_mut(idx) { + info.done_count += 1; + if info.done_count >= 2 { + state.try_finalize_output(idx); + } + } + } + } + _ => {} + } + } +} + +// --------------------------------------------------------------------------- +// Dispatch +// --------------------------------------------------------------------------- + +impl Dispatch for State { + fn event( + state: &mut Self, + _proxy: &ZxdgOutputV1, + event: ::Event, + data: &OutputId, + _conn: &wayland_client::Connection, + _qhandle: &QueueHandle>, + ) { + let target_name = data.0; + let idx = match &state.stage { + EncConstructionStage::ProbingOutputs { output_names, .. } => { + output_names.iter().position(|&n| n == target_name) + } + _ => None, + }; + let idx = match idx { + Some(i) => i, + None => return, + }; + + match event { + XdgOutputEvent::Name { name } => { + if let EncConstructionStage::ProbingOutputs { outputs, .. } = &mut state.stage { + if let Some(info) = outputs.get_mut(idx) { + info.name = Some(name); + } + } + } + XdgOutputEvent::LogicalPosition { x, y } => { + if let EncConstructionStage::ProbingOutputs { outputs, .. } = &mut state.stage { + if let Some(info) = outputs.get_mut(idx) { + info.logical_position = Some((x, y)); + } + } + } + XdgOutputEvent::LogicalSize { .. } => {} + XdgOutputEvent::Done => { + if let EncConstructionStage::ProbingOutputs { outputs, .. } = &mut state.stage { + if let Some(info) = outputs.get_mut(idx) { + info.done_count += 1; + if info.done_count >= 2 { + state.try_finalize_output(idx); + } + } + } + } + _ => {} + } + } +} + +// --------------------------------------------------------------------------- +// Dispatch +// --------------------------------------------------------------------------- + +impl Dispatch for State { + fn event( + _state: &mut Self, + _proxy: &ZwpLinuxDmabufV1, + event: ::Event, + _data: &(), + _conn: &wayland_client::Connection, + _qhandle: &QueueHandle>, + ) { + match event { + DmabufEvent::Format { .. } => {} + DmabufEvent::Modifier { .. } => {} + _ => {} + } + } +} + +impl Dispatch for State { + fn event( + state: &mut Self, + _proxy: &ZwpLinuxDmabufFeedbackV1, + event: ::Event, + _data: &(), + _conn: &wayland_client::Connection, + _qhandle: &QueueHandle>, + ) { + match event { + DmabufFeedbackEvent::MainDevice { device } => { + if device.len() >= 8 { + let dev_bytes: [u8; 8] = device[..8].try_into().unwrap_or([0u8; 8]); + let dev_t = u64::from_ne_bytes(dev_bytes); + let minor = (dev_t as u32) & 0xFFFFF; + let path = PathBuf::from(format!("/dev/dri/renderD{}", minor)); + if path.exists() { + tracing::info!("Compositor DRM device: {} (dev_t: {})", path.display(), dev_t); + state.drm_device_from_compositor = Some(path); + } else { + tracing::warn!( + "Compositor reported DRM device {} (dev_t: {}) but path does not exist", + path.display(), dev_t + ); + } + } else { + tracing::warn!("main_device event with unexpected data length: {}", device.len()); + } + } + DmabufFeedbackEvent::FormatTable { .. } => {} + DmabufFeedbackEvent::Done => {} + DmabufFeedbackEvent::TrancheDone => {} + DmabufFeedbackEvent::TrancheTargetDevice { .. } => {} + DmabufFeedbackEvent::TrancheFormats { .. } => {} + DmabufFeedbackEvent::TrancheFlags { .. } => {} + _ => {} + } + } +} + +// --------------------------------------------------------------------------- +// Dispatch +// --------------------------------------------------------------------------- + +impl Dispatch for State { + fn event( + _state: &mut Self, + _proxy: &ZwpLinuxBufferParamsV1, + event: ::Event, + _data: &(), + _conn: &wayland_client::Connection, + _qhandle: &QueueHandle>, + ) { + match event { + BufferParamsEvent::Created { .. } => { + tracing::debug!("DMA-BUF buffer created"); + } + BufferParamsEvent::Failed => { + tracing::error!("DMA-BUF buffer creation failed"); + } + _ => {} + } + } +} + +// --------------------------------------------------------------------------- +// Dispatch for CapWlrScreencopy +// --------------------------------------------------------------------------- + +impl Dispatch for State { + fn event( + state: &mut Self, + proxy: &ZwlrScreencopyFrameV1, + event: ::Event, + _data: &(), + _conn: &wayland_client::Connection, + _qhandle: &QueueHandle>, + ) { + match event { + ScreencopyFrameEvent::Buffer { .. } => { + tracing::warn!("Received SHM Buffer event — only DMA-BUF capture is supported. Ignoring."); + proxy.destroy(); + state.errored = true; + return; + } + ScreencopyFrameEvent::LinuxDmabuf { format, width, height } => { + tracing::debug!("Screencopy LinuxDmabuf: format={format}, {width}x{height}"); + if matches!(state.stage, EncConstructionStage::EverythingButFmt { .. }) { + state.negotiate_format(format, width, height); + if state.errored { + return; + } + } + if let EncConstructionStage::Streaming { cap, .. } = &mut state.stage { + cap.current_frame = Some(proxy.clone()); + } + state.on_frame_allocd((), format, width, height); + } + ScreencopyFrameEvent::Ready { tv_sec_hi, tv_sec_lo, tv_nsec } => { + let tv_sec = (tv_sec_hi as u64) << 32 | tv_sec_lo as u64; + let tv_usec = tv_nsec / 1000; + tracing::trace!("Screencopy ready: tv_sec={tv_sec}, tv_usec={tv_usec}"); + state.on_copy_complete(tv_sec, tv_usec); + } + ScreencopyFrameEvent::Failed => { + tracing::error!("Screencopy frame failed"); + state.on_copy_fail(); + } + ScreencopyFrameEvent::Damage { .. } => {} + _ => {} + } + } +} + +// --------------------------------------------------------------------------- +// Dispatch +// --------------------------------------------------------------------------- + +impl Dispatch for State { + fn event( + _state: &mut Self, + _proxy: &ZxdgOutputManagerV1, + _event: ::Event, + _data: &(), + _conn: &wayland_client::Connection, + _qhandle: &QueueHandle>, + ) { + } +} + +// --------------------------------------------------------------------------- +// Dispatch +// --------------------------------------------------------------------------- + +impl Dispatch for State { + fn event( + _state: &mut Self, + _proxy: &ZwlrScreencopyManagerV1, + _event: ::Event, + _data: &(), + _conn: &wayland_client::Connection, + _qhandle: &QueueHandle>, + ) { + } +} + +// --------------------------------------------------------------------------- +// Dispatch +// --------------------------------------------------------------------------- + +impl Dispatch for State { + fn event( + _state: &mut Self, + _proxy: &WlBuffer, + event: ::Event, + _data: &(), + _conn: &wayland_client::Connection, + _qhandle: &QueueHandle>, + ) { + if let wayland_client::protocol::wl_buffer::Event::Release = event { + tracing::trace!("WlBuffer released"); + } + } +} diff --git a/src/transform.rs b/src/transform.rs new file mode 100644 index 0000000..69e3e4c --- /dev/null +++ b/src/transform.rs @@ -0,0 +1,291 @@ +/// Coordinate transformation module for Wayland output transforms. +/// +/// Handles the 8 `wl_output` transform variants (rotation + reflection) +/// and ROI clipping for screen capture. +/// +/// Wayland output transform enum, matching `wl_output::Transform`. +#[derive(Debug, Clone, Copy, PartialEq, Eq)] +pub enum Transform { + Normal, + Normal90, + Normal180, + Normal270, + Flipped, + Flipped90, + Flipped180, + Flipped270, +} + +/// Axis-aligned rectangle in integer coordinates. +#[derive(Debug, Clone, Copy, PartialEq, Eq)] +pub struct Rect { + pub x: i32, + pub y: i32, + pub w: i32, + pub h: i32, +} + +/// Returns the 2×2 basis matrix (a, b, c, d) for the given transform. +/// +/// The matrix represents the affine mapping from screen coordinates to +/// frame coordinates: +/// +/// ```text +/// [new_x] [a b] [x] +/// [new_y] = [c d] [y] +/// ``` +pub fn transform_basis(transform: Transform) -> (i32, i32, i32, i32) { + match transform { + Transform::Normal => (1, 0, 0, 1), + Transform::Normal90 => (0, 1, -1, 0), + Transform::Normal180 => (-1, 0, 0, -1), + Transform::Normal270 => (0, -1, 1, 0), + Transform::Flipped => (-1, 0, 0, 1), + Transform::Flipped90 => (0, 1, 1, 0), + Transform::Flipped180 => (1, 0, 0, -1), + Transform::Flipped270 => (0, -1, -1, 0), + } +} + +/// Transform a rectangle from screen space to frame space. +/// +/// Applies the 2×2 basis matrix and computes offsets so the result +/// fits within the frame dimensions `(frame_w, frame_h)`. +/// +/// ```text +/// new_x = a * x + b * y + offset_x +/// new_y = c * x + d * y + offset_y +/// ``` +pub fn screen_to_frame( + transform: Transform, + rect: Rect, + frame_w: i32, + frame_h: i32, +) -> Rect { + let (a, b, c, d) = transform_basis(transform); + + // Compute the offset so that the transformed origin maps correctly. + // For transforms with negative components, we need to shift by the + // frame dimension to keep coordinates in [0, frame_w) × [0, frame_h). + let offset_x = if a + b < 0 { frame_w } else { 0 }; + let offset_y = if c + d < 0 { frame_h } else { 0 }; + + let new_x = a * rect.x + b * rect.y + offset_x; + let new_y = c * rect.x + d * rect.y + offset_y; + let new_w = a * rect.w + b * rect.h; + let new_h = c * rect.w + d * rect.h; + + Rect { + x: new_x, + y: new_y, + w: new_w.abs(), + h: new_h.abs(), + } +} + +/// Swap width and height for 90° or 270° rotations. +/// +/// After a quarter-turn rotation the output dimensions are transposed +/// relative to the input. This helper returns `(h, w)` for those cases +/// and `(w, h)` unchanged otherwise. +pub fn transpose_if_transform_transposed(transform: Transform, w: i32, h: i32) -> (i32, i32) { + match transform { + Transform::Normal90 | Transform::Normal270 | Transform::Flipped90 | Transform::Flipped270 => { + (h, w) + } + _ => (w, h), + } +} + +/// Clip a rectangle so it stays inside `(0, 0) .. (bounds_w, bounds_h)`. +/// +/// The resulting rectangle has non-negative origin and its extent does +/// not exceed the bounds. +pub fn fit_inside_bounds(rect: Rect, bounds_w: i32, bounds_h: i32) -> Rect { + let x = rect.x.clamp(0, bounds_w); + let y = rect.y.clamp(0, bounds_h); + let right = (rect.x + rect.w).min(bounds_w); + let bottom = (rect.y + rect.h).min(bounds_h); + let w = (right - x).max(0); + let h = (bottom - y).max(0); + Rect { x, y, w, h } +} + +#[cfg(test)] +mod tests { + use super::*; + + // ── transform_basis ─────────────────────────────────────────── + + #[test] + fn basis_normal_is_identity() { + assert_eq!(transform_basis(Transform::Normal), (1, 0, 0, 1)); + } + + #[test] + fn basis_90_cw_rotation() { + assert_eq!(transform_basis(Transform::Normal90), (0, 1, -1, 0)); + } + + #[test] + fn basis_180_rotation() { + assert_eq!(transform_basis(Transform::Normal180), (-1, 0, 0, -1)); + } + + #[test] + fn basis_270_cw_rotation() { + assert_eq!(transform_basis(Transform::Normal270), (0, -1, 1, 0)); + } + + #[test] + fn basis_flipped_horizontal() { + assert_eq!(transform_basis(Transform::Flipped), (-1, 0, 0, 1)); + } + + #[test] + fn basis_flipped_90() { + assert_eq!(transform_basis(Transform::Flipped90), (0, 1, 1, 0)); + } + + #[test] + fn basis_flipped_180() { + assert_eq!(transform_basis(Transform::Flipped180), (1, 0, 0, -1)); + } + + #[test] + fn basis_flipped_270() { + assert_eq!(transform_basis(Transform::Flipped270), (0, -1, -1, 0)); + } + + // ── screen_to_frame ─────────────────────────────────────────── + + #[test] + fn screen_to_frame_identity_unchanged() { + let rect = Rect { x: 10, y: 20, w: 100, h: 50 }; + let result = screen_to_frame(Transform::Normal, rect, 1920, 1080); + assert_eq!(result, Rect { x: 10, y: 20, w: 100, h: 50 }); + } + + #[test] + fn screen_to_frame_90_rotates_origin() { + // 90° CW: top-left (0,0) in screen should map to bottom-left in frame + let rect = Rect { x: 0, y: 0, w: 100, h: 50 }; + let result = screen_to_frame(Transform::Normal90, rect, 1080, 1920); + // a=0,b=1,c=-1,d=0 => offset_x=0, offset_y=1920 (c+d=-1<0) + // new_x = 0*0 + 1*0 + 0 = 0 + // new_y = -1*0 + 0*0 + 1920 = 1920 + assert_eq!(result.x, 0); + assert_eq!(result.y, 1920); + // w' = 0*100 + 1*50 = 50, h' = -1*100 + 0*50 = -100 -> abs=100 + assert_eq!(result.w, 50); + assert_eq!(result.h, 100); + } + + #[test] + fn screen_to_frame_180_rotates() { + let rect = Rect { x: 100, y: 200, w: 300, h: 400 }; + let result = screen_to_frame(Transform::Normal180, rect, 1920, 1080); + // a=-1,b=0,c=0,d=-1, offset_x=1920, offset_y=1080 + assert_eq!(result.x, -100 + 1920); + assert_eq!(result.y, -200 + 1080); + assert_eq!(result.w, 300); + assert_eq!(result.h, 400); + } + + #[test] + fn screen_to_frame_flipped_horizontal() { + let rect = Rect { x: 50, y: 30, w: 200, h: 100 }; + let result = screen_to_frame(Transform::Flipped, rect, 1920, 1080); + // a=-1,b=0,c=0,d=1, offset_x=1920, offset_y=0 + assert_eq!(result.x, -50 + 1920); + assert_eq!(result.y, 30); + assert_eq!(result.w, 200); + assert_eq!(result.h, 100); + } + + // ── transpose_if_transform_transposed ───────────────────────── + + #[test] + fn transpose_normal_no_swap() { + assert_eq!(transpose_if_transform_transposed(Transform::Normal, 1920, 1080), (1920, 1080)); + } + + #[test] + fn transpose_90_swaps() { + assert_eq!(transpose_if_transform_transposed(Transform::Normal90, 1920, 1080), (1080, 1920)); + } + + #[test] + fn transpose_180_no_swap() { + assert_eq!(transpose_if_transform_transposed(Transform::Normal180, 1920, 1080), (1920, 1080)); + } + + #[test] + fn transpose_270_swaps() { + assert_eq!(transpose_if_transform_transposed(Transform::Normal270, 1920, 1080), (1080, 1920)); + } + + #[test] + fn transpose_flipped_no_swap() { + assert_eq!(transpose_if_transform_transposed(Transform::Flipped, 1920, 1080), (1920, 1080)); + } + + #[test] + fn transpose_flipped90_swaps() { + assert_eq!(transpose_if_transform_transposed(Transform::Flipped90, 1920, 1080), (1080, 1920)); + } + + #[test] + fn transpose_flipped180_no_swap() { + assert_eq!(transpose_if_transform_transposed(Transform::Flipped180, 1920, 1080), (1920, 1080)); + } + + #[test] + fn transpose_flipped270_swaps() { + assert_eq!(transpose_if_transform_transposed(Transform::Flipped270, 1920, 1080), (1080, 1920)); + } + + // ── fit_inside_bounds ───────────────────────────────────────── + + #[test] + fn fit_inside_already_fits() { + let rect = Rect { x: 10, y: 20, w: 100, h: 50 }; + let result = fit_inside_bounds(rect, 1920, 1080); + assert_eq!(result, rect); + } + + #[test] + fn fit_inside_clips_right_and_bottom() { + let rect = Rect { x: 1800, y: 1000, w: 200, h: 200 }; + let result = fit_inside_bounds(rect, 1920, 1080); + assert_eq!(result, Rect { x: 1800, y: 1000, w: 120, h: 80 }); + } + + #[test] + fn fit_inside_clips_negative_origin() { + let rect = Rect { x: -50, y: -30, w: 200, h: 200 }; + let result = fit_inside_bounds(rect, 1920, 1080); + assert_eq!(result, Rect { x: 0, y: 0, w: 150, h: 170 }); + } + + #[test] + fn fit_inside_completely_out_of_bounds() { + let rect = Rect { x: 2000, y: 2000, w: 100, h: 100 }; + let result = fit_inside_bounds(rect, 1920, 1080); + assert_eq!(result, Rect { x: 1920, y: 1080, w: 0, h: 0 }); + } + + #[test] + fn fit_inside_zero_size_rect() { + let rect = Rect { x: 100, y: 100, w: 0, h: 0 }; + let result = fit_inside_bounds(rect, 1920, 1080); + assert_eq!(result, Rect { x: 100, y: 100, w: 0, h: 0 }); + } + + #[test] + fn fit_inside_zero_bounds() { + let rect = Rect { x: 0, y: 0, w: 100, h: 100 }; + let result = fit_inside_bounds(rect, 0, 0); + assert_eq!(result, Rect { x: 0, y: 0, w: 0, h: 0 }); + } +} diff --git a/tests/integration_test.rs b/tests/integration_test.rs new file mode 100644 index 0000000..7183fce --- /dev/null +++ b/tests/integration_test.rs @@ -0,0 +1,103 @@ +use std::process::Command; + +/// Helper: get the binary path. Uses the release build if available. +fn bin_path() -> &'static str { + "target/release/wl-webrtc" +} + +#[test] +fn test_help_flag() { + let output = Command::new(bin_path()) + .arg("--help") + .output() + .expect("failed to execute wl-webrtc --help"); + + let stdout = String::from_utf8_lossy(&output.stdout); + assert!(output.status.success(), "--help should exit 0"); + assert!( + stdout.contains("output"), + "help output should mention 'output'" + ); + assert!(stdout.contains("fps"), "help output should mention 'fps'"); + assert!( + stdout.contains("codec"), + "help output should mention 'codec'" + ); + assert!( + stdout.contains("bitrate"), + "help output should mention 'bitrate'" + ); + assert!( + stdout.contains("gop-size"), + "help output should mention 'gop-size'" + ); + assert!( + stdout.contains("drm-device"), + "help output should mention 'drm-device'" + ); +} + +#[test] +fn test_rejects_invalid_args() { + let output = Command::new(bin_path()) + .arg("--nonexistent-flag-xyz") + .output() + .expect("failed to execute wl-webrtc with invalid args"); + + assert!( + !output.status.success(), + "should reject unrecognized flag" + ); + let stderr = String::from_utf8_lossy(&output.stderr); + assert!( + stderr.to_lowercase().contains("error") + || stderr.to_lowercase().contains("unexpected") + || stderr.to_lowercase().contains("unrecognized"), + "stderr should mention the error, got: {stderr}" + ); +} + +#[test] +fn test_rejects_hevc_codec() { + let output = Command::new(bin_path()) + .arg("--output") + .arg("/dev/null") + .arg("--codec") + .arg("hevc") + .output() + .expect("failed to execute wl-webrtc --codec hevc"); + + // MVP only supports h264; hevc should be rejected. + assert!( + !output.status.success(), + "should reject hevc codec in MVP" + ); +} + +/// Tests requiring a live Wayland compositor and VAAPI hardware. +/// Run with: cargo test -- --ignored +#[test] +#[ignore] +fn test_capture_starts_with_valid_output() { + // This test requires: + // - A running Wayland compositor + // - VAAPI-compatible GPU hardware + // - A writable output path + let output = Command::new(bin_path()) + .arg("--output") + .arg("/tmp/wl-webrtc-test-capture.mp4") + .arg("--fps") + .arg("10") + .output() + .expect("failed to start wl-webrtc"); + + // If we get here, the process ran and exited. + // In a real test, we'd give it time to capture a few frames + // and then send SIGINT, but for now just check it didn't + // immediately fail with an argument error. + let stderr = String::from_utf8_lossy(&output.stderr); + assert!( + !stderr.contains("error: unexpected") && !stderr.contains("error: invalid"), + "should not have argument parsing errors, got: {stderr}" + ); +}