# 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

# WebRTC streaming mode (HTTP signaling server)
wl-webrtc --port 8080 -v

# Force a fresh portal authorization dialog (ignore saved restore token)
wl-webrtc --output output.mp4 --no-persist

# Pin the capture backend instead of auto-detecting
wl-webrtc --output output.mp4 --backend portal    # or: --backend screencopy
```

## CLI Arguments

> `src/args.rs` is the authoritative source. Run `wl-webrtc --help` for the live list.

| Argument | Default | Description |
|---|---|---|
| `-o`, `--output` | (optional) | Output file path (e.g. output.mp4). Optional when using `--port` for WebRTC mode. |
| `--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 |
| `--max-bitrate` | 8000000 | Max bitrate cap for WebRTC mode (caps BWE escalation; no effect in MP4 mode) |
| `--gop-size` | auto | Group of Pictures size |
| `-v`, `--verbose` | false | Enable verbose logging |
| `--backend` | auto | Capture backend: `screencopy` (wlroots) or `portal` (KWin/KDE). Auto-detected if omitted. |
| `--port` | 0 | WebRTC HTTP signaling server port. `0` keeps MP4 file output mode. |
| `--no-persist` | false | Force re-authorization (ignore saved portal restore token) |
| `--stats` | false | Print per-second pipeline statistics for stutter diagnosis |

## Capture backends

The tool supports two Wayland capture backends, auto-detected by default:

- **wlr-screencopy** (preferred when `zwlr_screencopy_manager_v1` is advertised):
  works on wlroots-based compositors (Sway, Hyprland, etc.).
- **XDG Portal / PipeWire** (fallback when D-Bus ScreenCast is available):
  works on KWin/KDE and any compositor that implements the XDG Desktop Portal
  screen-cast protocol. The first run shows an authorization dialog; a restore
  token is cached under `wl-webrtc/portal-restore-token` so subsequent runs
  don't re-prompt (use `--no-persist` to force a fresh authorization).