Web speakers (kixelated/hang reference) emit stereo Opus when the
user's AudioContext picks a stereo input — and our catalog now lets
us know that ahead of decoder construction. Previously the decoder
+ AudioTrack were both hardcoded to mono via AudioFormat.CHANNELS, so
a stereo web publisher's frames either threw on the Opus TOC byte
mismatch, decoded with downmix artifacts, or output left-channel-only
depending on the device's MediaCodec implementation.
Wire the catalog-discovered numberOfChannels through:
- MediaCodecOpusDecoder accepts `channelCount: Int = 1`. Drives
MediaFormat.createAudioFormat's channel count, the OpusHead CSD-0
channel byte, and the per-frame output buffer size (stereo frame =
2× shorts vs mono). Validates 1..2 — RFC 7845 mapping family 0
covers both mono and stereo without an explicit channel mapping
table; multichannel needs family 1 which we don't support.
- AudioTrackPlayer accepts `channelCount: Int = 1`. Drives the
AudioTrack channel mask (CHANNEL_OUT_MONO vs CHANNEL_OUT_STEREO)
and the 250 ms wall-clock buffer-size target (stereo doubles bytes
per sample).
- NestViewModel.openSubscription now starts the catalog fetch
BEFORE waiting for it, then awaits `_speakerCatalogs[pubkey]` for
CATALOG_AWAIT_TIMEOUT_MS (500 ms) before constructing the decoder
+ player. With the speaker-side emit-on-subscribe hook in place
(3417e44), the catalog frame is on the wire within one round-trip
of the SUBSCRIBE_OK, so the wait typically resolves in tens of ms.
Falls back to mono if the catalog never arrives — covers legacy
publishers that don't emit a catalog and the failure-mode where
the relay never forwards the catalog group.
- decoderFactory + playerFactory signatures change from
`() -> X` to `(channelCount: Int) -> X`. Two call sites updated:
NestViewModelFactory (production) and NestViewModelTest's
newViewModel helper.
Speaker side stays mono-only — our encoder is fixed at
AudioFormat.CHANNELS=1 and the catalog we publish declares
numberOfChannels=1. This change is exclusively about handling
incoming audio from publishers that don't share that constraint.
https://claude.ai/code/session_014JfZJHSTvyYYWJbC9VbB47
Claude
1c47fd2403