The residual padding in the ALSA tee was the guest running at 0.70x real time,
and the dominant load is llvmpipe software rendering -- which an audio capture
does not need at all.
PulseAudio monitor, xenia default 39.3 percent silence 30.5 gaps/s
ALSA tee to paced slave, rendered 9.98 percent silence 8.37 gaps/s
ALSA tee to paced slave, --gpu=null 0.31 percent silence 0.01 gaps/s
One gap in 67.7 s. Six distinct channels, no duplicates, sensible peaks. For
scale the port s genuine music bed control measures 1.1 percent silence at 3.3
gaps/s, so this capture is cleaner than their known-good reference.
Control that the run is still comparable: ADV s three XMA contexts appear in the
--gpu=null log, so the movie s voice is decoding exactly as in a rendered boot.
That is also better provenance for an audio question than screenshots were, since
it evidences the thing being recorded rather than what was on screen.
Records the full working recipe. Caveat: --gpu=null means no video, so
screen-based provenance is unavailable and it is only appropriate when the
question is about audio.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QsEPXWVaEpyfudtR6re1Pd
41b47fa281