PipeWire spa_meta_header.pts is CLOCK_MONOTONIC in nanoseconds, but the
encoder expects frame-number units (time_base = 1/fps). The raw nanosecond
value was assigned directly to AVFrame.pts, causing the encoder/muxer to
interpret timestamps as billions of frames, producing corrupted duration
metadata and broken rate control.
Fix: record the first frame's PTS as a nanosecond base, compute elapsed
nanoseconds for each subsequent frame, then convert to frame numbers via
elapsed_ns * fps / 1_000_000_000. Using elapsed time avoids i64 overflow
on absolute timestamps (~10^18 ns).
Matches the WLR path pattern (state.rs:525-527) which converts microseconds
to frame numbers for the same encoder.
PipeWire .process callback called frame_tx.send() on a bounded(3)
channel. If the encoder stalled, this blocked the PipeWire data loop,
delaying buffer recycling and potentially causing XRUNs.
Replace with try_send + AtomicU64 drop counter. Frames are silently
dropped when the channel is full (preferred for screen capture: latest
frame wins). A warning is logged every 30 dropped frames.
Fixes#2 from BUGS.md.
The detached helper thread that called pw_main_loop_quit() through a raw
pointer cast to usize could outlive the mainloop if run() returned on its
own (event loop error, panic in callback, etc.), causing use-after-free.
Replace with an eventfd registered on the PipeWire loop via add_io(). The
shutdown callback runs on the loop thread during mainloop.run(), where the
mainloop is guaranteed alive. Drop order (reverse declaration) ensures the
IO source is unregistered before mainloop is destroyed.
Fixes: #1 (Critical UAF)
Add a second capture backend for compositors without wlr-screencopy
(KWin, GNOME, etc.) using the xdg-desktop-portal ScreenCast interface
and PipeWire DMA-BUF streaming.
New files:
- src/backend_detect.rs: auto-detect wlr-screencopy vs portal backend
- src/cap_portal.rs: Portal session setup + PipeWire DMA-BUF thread
- src/state_portal.rs: StatePortal encoder pipeline (DMA-BUF → VAAPI)
Changes:
- Cargo.toml: add ashpd 0.13, tokio 1, pipewire 0.9, libspa 0.9,
crossbeam-channel 0.5
- src/args.rs: add --backend CLI flag
- src/avhw.rs: extract create_encoder() from inline State code
- src/main.rs: route to portal or wlr-screencopy based on backend
- src/state.rs: fix params.destroy() on dup failure, cleanup
in_flight_surface on copy fail, use create_encoder()
- tests/integration_test.rs: add --backend flag tests
dailz