fix: preserve audio sample continuity across timestamp rounding

README.md

@@ -32,6 +32,10 @@ make check
 
 Generates short fixtures and exercises the real playback interface and native outputs: audio/video, video-only, audio-only, pause, paused/playing seek, completion, replay, close, HDR rejection, failed-open recovery, and destruction while playing. It initializes the actual Metal shaders and uses an offscreen native window. It requires a working audio device and graphical macOS session, and plays short sine-wave audio. It is a runtime smoke check, not a mocked clock/device test.
 
+`make check-audio` runs just the audio-quality check. A check-only hook captures actual Core Audio callback PCM into preallocated storage and compares every sample against FFmpeg's reference output for PCM/AAC, 44.1/48 kHz, and coarse container timestamps. A separate gapped fixture verifies that real timestamp gaps remain silent. Release builds contain no capture hook.
+
+Continuous audio uses resampled sample counts for its output timeline; packet timestamp quantization and rounded resampler delay must not insert silence or drop samples between blocks.
+
 Visual correctness, perceived A/V synchronization, and control usability still need a check in the visible app.
 
 ## Current limits