fix(playback): backward seek freeze from epoch/monotonic clock mismatch - #350
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Root cause: _seekStartedAtMs was recorded with performance.now() but the
timeout check in _tick() compared against Date.now() (Unix epoch). The
delta was always ~1.77 trillion ms, causing completeSeek() to fire on the
very first tick after any seek — clearing _isSeeking before the seek
settled.
PlaybackClock.ts setNativeClockPosition() guards stale backward audio
samples with:
return // discard stale sample
With _isSeeking forced false immediately, every backward audio sample was
discarded as 'stale'. Forward seeks were unaffected because clampedTime >
_time always passes the guard.
PlaybackClock.ts:
- Switch _tick() seek timeout check from Date.now() to performance.now()
so elapsed time is measured in the same monotonic domain as _seekStartedAtMs
- Reset _nativeClockPosition = null on paused seeks so stale native samples
do not pollute the new seek position
- Align _nativeClockPosition to this._time immediately on seek-- Align _nativeClockPosition to this._time immediately on seek-- Ali the - Align _nativeClockPosition to this._time immediately on seek-- Aligoo- Align _nativeClockPosition to this._time immediately on seek-- Align _ s- Align _nativeClockPosition to this._time immediately on seek-- Aligme; previously forceRenderNeeded was set but the
RAF loop was not woken, causing settling fram RAF loop was not woken, causing settling fram RAF loop was not woken, ca10 files);
preview suite 188/188 (16 files)
theunavailableguy
approved these changes
Sep 21, 2026
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Fixes backward seeks not updating the program preview, introduced by the BUG-5 seek timeout check.
Root cause: _seekStartedAtMs was recorded with performance.now() but _tick() checked Date.now(). The ~1.77 trillion ms delta caused completeSeek() to fire on the first tick, clearing _isSeeking immediately. setNativeClockPosition() then discarded every backward audio sample as stale. Forward seeks were unaffected.
PlaybackClock.ts: Date.now() -> performance.now() in timeout check; reset _nativeClockPosition on paused seeks; align _nativeClockPosition to this._time on seek-while-playing.
NativeProgramPreview.tsx: Add wakeNativeRenderLoopRef.current?.() in seekController.subscribe() when isSettling so the RAF loop is actually woken for settling frames.
Verified: tsc clean; playback 72/72; preview 188/188.