Moves the full capture+encode+mux pipeline into gst-launch, leaving
ffmpeg as a thin HTTP server. Verified end-to-end on KDE Plasma 6
Wayland: screencast portal → mpv mirror-tunnel rendering in real time.
Pipeline:
pipewiresrc(do-timestamp) → videoconvert → x264enc (zerolatency
ultrafast) → h264parse(config-interval=-1) → byte-stream caps →
mpegtsmux ← (aacparse ← avenc_aac ← audioconvert ← pulsesrc) →
fdsink fd=1
ffmpeg -fflags nobuffer+discardcorrupt+genpts -flags low_delay
-analyzeduration 0 -probesize 32 -f mpegts -i pipe:0 -c copy
-f mpegts -listen 1 http://127.0.0.1:N
Why each piece is load-bearing (do not relitigate without cause):
- x264enc + h264parse + byte-stream caps: raw video over a pipe hits
stride/format negotiation problems (green screens with mis-aligned
rows). Encoding inside gst sidesteps that entirely.
- mpegtsmux inside gst: H.264 Annex B carries no timestamps. Without
a container, ffmpeg sees "Timestamps are unset" and downstream
muxing breaks. mpegts in gst preserves pipewiresrc's clock.
- byte-stream + alignment=au caps: h264parse defaults to AVC format
(length-prefixed NALUs) for some downstreams; ffmpeg's mpegts
demuxer needs Annex B start codes.
- audio in gst (pulsesrc + avenc_aac): keeping ffmpeg as a pure
passthrough (`-c copy`) avoids ffmpeg's audio-input dependency
delaying HTTP serving until both inputs are ready.
- `-analyzeduration 0 -probesize 32`: stop ffmpeg from buffering 5MB
/ 5s of input before deciding it understands the stream.
- Also fixes a separate one-shot bug from earlier: the previous
health-probe in wait_for_listener consumed ffmpeg's single
`-listen 1` accept slot, so the actual bridge connect hit
Connection refused. Replaced with connect_to_capture which
returns the bridge socket.
Adds dep checks for pipewiresrc, x264enc, h264parse, mpegtsmux,
pulsesrc, avenc_aac, aacparse with per-distro install hints.
Known gap: VLC currently shows a green screen against the stream
even though mpv works fine. Likely VLC-specific demuxer/latency
settings, not a pipeline correctness issue — to investigate as a
follow-up. mpv is the recommended client either way.
mollusk
75a01a361e