CasparCG's bundled FFMPEG/HLS consumer muxes a broken audio track
(aac sample_rate=0, time_base 1/0) into the preview, and silently drops
every arg that would remove it (-an, -codec:a, -g, -r all "Unused
option"). That corrupt audio black-screens the browser preview because
neither ffmpeg nor hls.js can decode the playlist.
Re-architect the preview path: CasparCG now STREAMs plain mpegts to a
UDP loopback port, and a Node-spawned STANDALONE ffmpeg (where -an
actually works) re-muxes it to clean, video-only HLS with -c:v copy.
The child process is tracked, auto-respawned while running, and killed
in stopChannel(). The PRIMARY SRT/RTMP/SDI/NDI output (with program
audio) is untouched.
Also fix the Dockerfile to match the working image: ubuntu:22.04 base +
CasparCG 2.4.0 ubuntu22 zip + NodeSource Node 20, and add a standalone
ffmpeg CLI. The old 2.3.3 tarball URL 404s. entrypoint.sh updated for
the 2.4.x bin/casparcg layout + bundled lib/ LD_LIBRARY_PATH.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
One container per channel. Built like capture/build-with-decklink: NDI +
DeckLink SDKs fetched at build, runs --privileged with Xvfb for the GL
context where no real display is present.
Components:
- entrypoint.sh: Xvfb + CasparCG launch, creates /media/live/<CHANNEL_ID>
- src/amcp.js: TCP AMCP client
- src/playout-manager.js: channel lifecycle, playlist walk via LOADBG AUTO
for gapless transitions; primary consumer (decklink/ndi/srt/rtmp) plus a
second FFMPEG HLS consumer (~600 kbps, 2s segments) for the UI preview
- src/index.js: HTTP shim — /channel/start, /playlist/load, transport
- frame-rate helper picks fps from video_format (59.94 → 60000/1001) so
SEEK / LENGTH frame math is correct
