MTAudioProcessingTap with AVPlayerItem.audioMix doesn't fire its process
callback for HLS streams on macOS (known limitation). This caused recorded
videos to have no audio track when recording HLS content.
Replace with CoreAudio AudioDeviceCreateIOProcID approach that captures
PCM audio directly from the system output device. This works for all
audio sources (HLS, local files, etc).
Key changes:
- Remove MTAudioProcessingTap and all tap callbacks
- Add CoreAudio device IOProc for audio capture
- Pre-allocated buffer to avoid malloc in real-time audio thread
- Serial dispatch queue for CMSampleBuffer processing off audio thread
- AudioTimeStamp → CMTime conversion for proper timestamps
yumoqing
f1ecbf2e91