Phase 4 (codec + audio capture slice). Adds the publisher-side MoQ
control messages and the Opus encode + microphone capture pieces a
speaker needs. The host-grants-speaker UI flow is deferred — that's
multi-screen UX that should be designed before being implemented.
commonMain (nestsclient.moq):
- 5 new MoqMessageType entries with codec round-trip + tests:
* Announce (0x06): publisher offers a track namespace.
* AnnounceOk (0x07): subscriber acknowledges.
* AnnounceError (0x08): subscriber rejects with error code +
reason phrase.
* Unannounce (0x09): publisher withdraws a previously-announced
namespace.
* SubscribeDone (0x0B): publisher tells the subscriber no more
objects are coming for this subscription, with stream count and
reason.
commonMain (nestsclient.audio):
- New `OpusEncoder` interface — symmetric to `OpusDecoder`, one
instance per outgoing track since Opus state is per-stream.
- New `AudioCapture` interface — `start()`, `readFrame()` returns a
PCM frame or null when stopped, `stop()` releases the mic.
androidMain (nestsclient.audio):
- `MediaCodecOpusEncoder` — wraps `MediaCodec("audio/opus")` encoder
variant (API 29+). 48 kHz mono in, 32 kbit/s VBR Opus out, 20 ms
frames. Drains output queue per encode call.
- `AudioRecordCapture` — wraps `AudioRecord` from
`MediaRecorder.AudioSource.VOICE_COMMUNICATION` so the platform's
echo-cancellation + noise-suppression filters apply when available.
Reads exactly one PCM frame per readFrame() call, retries on
underrun, throws AudioException(DeviceUnavailable) on permission/
resource failures.
commonTest:
- `AnnounceCodecTest` — 7 cases covering each message round-trip,
concatenated decode in sequence, and a guard against accidentally
reordering MoqMessageType enum codes.
Permission already declared:
- `RECORD_AUDIO` is already in amethyst/AndroidManifest.xml — no
manifest change needed.
What this does NOT include:
- A publisher loop class (analogous to AudioRoomPlayer for publish
direction) — can be added when the speak-button wiring lands.
- The host-grants-speaker UI — needs design input.
- STREAM_HEADER_SUBGROUP for stream-based object delivery — datagrams
cover the listener happy-path; streams add reliability that nests
may or may not require.
https://claude.ai/code/session_013nVLALALKaHVgHm9u5Cg8D
Phase 3d-1 of the Clubhouse/nests integration. Adds the listener-side
audio pipeline that turns a SubscribeHandle's Flow<MoqObject> into
audible PCM through Android's MediaCodec + AudioTrack. Encoder /
AudioRecord (speaker publishing) lands in Phase 4.
commonMain (nestsclient.audio):
- `AudioFormat` constants — 48 kHz mono signed-16-bit, 20 ms frames
(960 samples), matching the nests Opus profile.
- `OpusDecoder` interface — stateful per-track decoder.
- `AudioPlayer` interface — start/enqueue/stop, suspend on backpressure.
- `AudioRoomPlayer` — wires a Flow<MoqObject> through OpusDecoder into
AudioPlayer. Decoder errors are surfaced via an `onError` callback
but don't tear down the loop (one bad packet shouldn't kill the
room); player errors are fatal. play()/stop() are single-shot per
instance, with stop() idempotent and double-release-safe.
- `AudioException` with three canonical kinds (DecoderError,
DeviceUnavailable, PlaybackFailed).
androidMain:
- `MediaCodecOpusDecoder` — wraps `MediaCodec("audio/opus")` with the
RFC 7845 §5.1 Opus identification header in csd-0 and zeroed
pre-skip / seek-pre-roll in csd-1 / csd-2. Drains the output queue
per-packet, handles INFO_OUTPUT_FORMAT_CHANGED gracefully.
- `AudioTrackPlayer` — wraps `AudioTrack` in MODE_STREAM with USAGE_
VOICE_COMMUNICATION / CONTENT_TYPE_SPEECH so the OS treats audio-
room playback like a phone call (call-volume rocker, ducks
notifications). Buffer = 4× minimum so the producer can fall behind
~80 ms (roughly the WebTransport datagram jitter on mobile).
Tests (commonTest, fake-based):
- `AudioRoomPlayerTest` — 7 cases covering happy-path decode +
enqueue, decoder failure with continued loop, stop idempotency,
double-play rejection, play-after-stop rejection, empty-PCM
skip-enqueue, and live channel-backed flow.
The real MediaCodec / AudioTrack code is thin glue against Android
APIs and is validated manually on device — no Robolectric here, the
seams are the Fake* doubles.
Next: Phase 3d-2 wires NestsClient end-to-end (HTTP auth → MoqSession
listener subscribe → AudioRoomPlayer) plus the Amethyst-side
AudioRoomViewModel. After that the only remaining pure-MoQ work is
the Kwik handshake (Phase 3b-2).
https://claude.ai/code/session_013nVLALALKaHVgHm9u5Cg8D
Claude