dailz a83d146ed3 fix: FPS limiter never passes frames when input > target rate
The old FpsLimit compared timestamps between CONSECUTIVE frames.
When PipeWire delivers at 60fps (16ms intervals) and target is 30fps
(33ms min_interval), the gap between consecutive frames is always
16ms < 33ms, so EVERY frame was rejected after the first.

Fix: track last_output_time and compare against that instead of the
previous frame's timestamp. Now frames pass when enough time has
elapsed since the last OUTPUT, not since the last INPUT.

Also adds PipeWire process callback counter logging and frame
diagnostic STATS in state_portal.rs for debugging.
2026-05-29 22:09:35 +08:00

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

cargo build --release

Run

# 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)
Description
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