fegger
3f8e92c6af
The first real sender/receiver run failed permanently: the receiver reported 'non-existing PPS 0' for every frame. Without a VBV, a 2256x1504 IDR keyframe bursts hundreds of kilobytes of back-to-back FU-A packets, overflowing the ~208KB default UDP receive buffer; the resulting sequence gap made the depacketizer drop whole keyframes including their in-band SPS/PPS, so the decoder never initialized and never recovered, because every keyframe burst overflowed again. - Encoder: add rc_max_rate = bitrate and rc_buffer_size = bitrate*2/fps, capping any single frame to about two frame periods of bytes (~40KB at the 4Mbps default). - Encoder: switch the time_base to microseconds. It was derived from the configured frame rate, which quantized capture-rate timestamps and duplicated pts; RTP timestamps are now lossless. - Transport: request a 4MB SO_RCVBUF on the receive socket (best-effort; the kernel clamps to net.core.rmem_max). meson test 4/4, valgrind clean (loopback + codec).
82 lines
3.0 KiB
Markdown
82 lines
3.0 KiB
Markdown
# Runbook — build and validation commands
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Reusable validation steps for this repository. Run the relevant ones before
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considering a change complete.
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## Build and test
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```sh
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meson setup build # once
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meson compile -C build
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meson test -C build --print-errorlogs
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```
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## Memory and correctness checks (codec changes)
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Run the codec round-trip test under valgrind after touching the encoder or
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decoder:
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```sh
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valgrind --leak-check=full --errors-for-leak-kinds=definite \
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build/tests/test_codec_roundtrip
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```
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Expected: no "definitely lost" bytes and no "Invalid read/write" errors.
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FFmpeg may keep some "still reachable" allocations at exit; that is normal.
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This check caught two real defects in the Phase 2 decoder: a per-packet
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payload leak and an unpadded extradata buffer over-read. Keep using it.
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## Capture smoke test (Phase 3, manual)
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Requires a running desktop session with `xdg-desktop-portal` and a backend
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that implements the ScreenCast portal (e.g. Hyprland, GNOME, KDE). The
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portal shows an interactive source picker, so this cannot run unattended.
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```sh
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meson compile -C build # builds tools/capture_smoke
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./build/tools/capture_smoke 10 out.h264 # captures 10 frames
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ffprobe -v error -show_entries stream=codec_name,width,height out.h264
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```
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Expected: the tool prints the negotiated resolution/format/stride and
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writes a non-empty file; `ffprobe` reports `codec_name=h264` and the correct
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width/height. The encoder prepends its Annex-B SPS/PPS extradata so the
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file is a self-contained elementary stream.
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If you see `impl_ext_end_proxy called from wrong context` warnings, a
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PipeWire proxy operation ran without the thread-loop lock — all pw
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calls that send messages (connect, stream, core) must happen under
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`pw_thread_loop_lock`.
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## Sender / receiver loopback (Phase 5, manual)
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Two terminals on the same desktop session:
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```sh
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./build/src/app/screencast --receive # terminal 1: window appears
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./build/src/app/screencast --send # terminal 2: portal source picker
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```
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Expected: the receiver window shows the captured desktop in near real time.
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If the receiver starts after the sender, a few `non-existing PPS` decode
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errors are normal until the next keyframe arrives (the GOP is ~0.4s);
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video should appear within a second. Stop either side with Ctrl-C.
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Optional flags: `--port`, `--peer HOST[:PORT]`, `--bitrate KBPS`,
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`--target window`.
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Notes: the encoder runs a VBV that caps keyframe bursts to roughly two
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frame periods of bytes, and the receiver requests a 4MB UDP receive
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buffer (clamped by `net.core.rmem_max`). For very high `--bitrate`
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values, raise `net.core.rmem_max` on the receiver machine.
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The headless equivalent runs as part of `meson test` (`udp loopback` test):
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synthetic frames → encode → packetize → localhost UDP → depacketize →
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decode, no portal or window involved.
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## Formatting
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```sh
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find include src tests -type f \( -name '*.cpp' -o -name '*.h' \) \
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-exec clang-format --dry-run --Werror {} +
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``` |