## ADDED Requirements

### Requirement: P3D-014 hardware video presentation
Video SHALL use negotiated registered media identifiers, VideoToolbox hardware decode, and Metal presentation without unnecessary copies or persistence.

#### Scenario: Unsupported hardware decode
- **WHEN** the negotiated profile cannot be decoded by supported VideoToolbox hardware
- **THEN** the session fails explicitly without software fallback, remote transcode, or pixel logging

### Requirement: P3D-015 bounded audio playback
Audio SHALL use a proven CoreAudio abstraction with bounded buffering, negotiated channel layout, drift handling, and measurable A/V synchronization.

#### Scenario: Audio device replacement
- **WHEN** the default audio device changes or disappears during an active session
- **THEN** bounded playback state is recreated or fails visibly without persisting streamed audio