`AudioTrackPlayer` was constructing its `AudioTrack` with
`USAGE_VOICE_COMMUNICATION` + `CONTENT_TYPE_SPEECH` so the room would
behave like a phone call (volume rocker controls call volume, ducks
notifications). The `AudioTrack` then renders on `STREAM_VOICE_CALL`,
which Android only services audibly while the device is in
`MODE_IN_COMMUNICATION`. Nests never drives `AudioManager.mode` (only
NIP-100's `CallAudioManager` does), so on most devices the playback
either dropped to the earpiece at near-zero volume or produced no audio
at all — making rooms appear silent on both phones.
Fix: route through `USAGE_MEDIA` + `CONTENT_TYPE_SPEECH` (=
`STREAM_MUSIC`) so audio-room playback comes out of the loudspeaker by
default and the volume rocker controls it any time. Same approach
Twitter/X Spaces and Clubhouse take for hands-free audio rooms. Echo
cancellation still works on the capture side via
`MediaRecorder.AudioSource.VOICE_COMMUNICATION` regardless of the
playback usage.
Also update `NestForegroundService.requestAudioFocus` to request focus
under the matching `USAGE_MEDIA` attributes so the focus claim and the
playback attributes line up.
Claude
523e8a92ec