Extract the display-agnostic encode/mux tail out of wayland.rs into a new
host/pipeline.rs: CaptureHandle + lifecycle, audio routing setup, the gst
arg builder, the spawn, and Serve::bind now live there. Backends supply
only their video-source element args plus a post-spawn hook (Wayland uses
it to close its leaked pipewire fd; X11 passes a no-op). capture.rs
collapses to a thin dispatcher; its CaptureHandle enum is gone.
Add host/x11.rs: ximagesrc (use-damage=false show-pointer=true), whole
root window by default or a single window via --window (xwininfo
click-picker → xid). x11rb reads geometry for an info log, justifying the
previously-vestigial dep. No portal, no fd dance — capture starts
silently when the first viewer connects (the ticket is the access
control). Viewer is display-agnostic and unchanged.
Wire --no-hwencode for real (was a no-op): the shared tail now selects
x264enc(tune=zerolatency,ultrafast)/I420 vs vah264enc/NV12 and switches
the videoconvert target format to match. Applies to both backends.
deps.rs: check_host_binaries now takes &HostOpts and checks shared
elements for both backends, encoder by --no-hwencode, source per backend
(pipewiresrc/ximagesrc), and xwininfo only when X11 + --window. Install
hints added for x264enc, ximagesrc, xwininfo.
Verified: warning-free build; smoke test still passes (tail unchanged);
ximagesrc + both encoder tails produce mpv-decodable H.264 against an
Xwayland root. Interactive cross-machine end-to-end pending.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
`pulsesrc` with no `device=` reads PulseAudio's default source —
which is the user's microphone, not system audio output. The stream
was technically working but the laptop was hearing the desktop's
mic (or silence on systems without one) instead of system audio.
At host startup, shell out to `pactl get-default-sink` to discover
the current default sink, then pass `device=<sink>.monitor` to
pulsesrc. Resolving at session-start covers users who switch outputs
(speakers vs headset vs HDMI) between sessions. pactl added to the
host's required-binary list.
Verified cross-machine: audio came through clearly with the prior
~1s latency floor preserved.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
The previous ffmpeg-as-HTTP-server pipeline shape held back two
improvements at once. ffmpeg as the runtime server lost a one-shot
`-listen 1` accept to a probe-and-discard health check, and forced
us to size analyze/probe budgets carefully so ffmpeg would serve
before our deadline. Replacing it with a small tokio task that
accepts once, drains the HTTP request, writes a fixed 200 OK, then
`tokio::io::copy`s gst stdout to the socket removes all of that.
VAAPI H.264 (vah264enc) drops CPU encode from ~50% of a core to
single-digit %. An earlier attempt at vaav1enc had to be abandoned:
libavformat cannot demux AV1-in-MPEG-TS with the custom mapping
even with a 20MB probe budget — mpv reports video=eof. H.264 keeps
the hardware win on the well-trodden demuxer path.
scripts/smoke-pipeline.sh mirrors the runtime pipeline with
videotestsrc/audiotestsrc into a file and asserts that mpv reports
`video=playing` (not video=eof). The naive --frames=10 check was
a false positive when no video stream is recognized; the verbose
grep is the real gate.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
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.
`gst-launch-1.0` and `pipewiresrc` ship in separate packages on most
distros (Arch: `gst-plugin-pipewire`, Debian: `gstreamer1.0-pipewire`,
Fedora/openSUSE: `pipewire-gstreamer`). Having the gst binary present
was no guarantee the Wayland capture pipeline would actually work —
without the plugin gst would bail at runtime with `no element
"pipewiresrc"`, which then cascaded into ffmpeg seeing EOF on its
stdin and exiting before its HTTP listener bound, then the host
hitting "Connection refused" against its own port. Confusing.
Now `deps::check_host_binaries` probes `gst-inspect-1.0 --exists
pipewiresrc` on Wayland and fails early with a per-distro install
hint pointing at the right package.
mollusk