The waveform's ffmpeg decode + cavacore FFT pipeline lived inside
RealtimeWaveform, so switching away from the Player tab unmounted it and
killed the pipeline instantly — respawning ffmpeg on every return.
Move the pipeline into a module-level store (stores/visualizer.ts) that
outlives the page:
- losing Player-tab focus keeps the pipeline warm for
VISUALIZER_UNLOAD_DELAY_MS (30s), then tears it down (kills ffmpeg,
destroys the cava plan); regaining focus within the delay resumes the
warm pipeline with no restart churn; after an unload it restarts from
the current playback position.
- playback signals move to utils/audio-signals.ts (module-level, no
useAudio() owner needed) so the store reacts to play/pause/seek/speed
while no Player page is mounted; useAudio re-imports them.
- render a braille spinner as the loading state for the visualizer
(first play / after unload); stale bars stay on screen during warmup
restarts so the waveform never blanks out for the network-bound cold
start.
- seed the smooth position clock at pipeline start: with the position
still frozen at 0 while mpv opens the stream, the reader sampled a
1-sample window that could never fill, starving the bars until mpv's
first poll.
Pins the store contract in tests/visualizer-store.test.ts: loading→bars,
warm resume without restart, 30s unload, and bars while position is
frozen at 0.
Michael Freno
8496922aaf