Since #103, a preview with audio stayed silent until every frame from
the playhead to the end of the preview (or what fits in the RAM
preview) was cached. The prefetch only renders a few frames ahead, so
on a normal work area the sound came near the end or on the second
loop, even when the comp rendered in real time.
The held sound now also starts once the silent preview has kept real
time for a quarter second with the prefetch window ahead cached. A
comp that can't render in real time still waits for the cache, as #103
intended; a stall clears the measured rate so the sound doesn't cut in
and out.
Test: preview_with_audio_sounds_once_rendering_keeps_up (a 30 s comp
sounds within 2 s, without skipping a frame first).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_018gnTnH3Jmk5zr4tMq1Mc9f
6e31677718