G4: Audit-9 (catalog-driven decoder reconfig) plumbed numberOfChannels
end-to-end but left sampleRate hardcoded at AudioFormat.SAMPLE_RATE_HZ
in MediaCodecOpusDecoder.buildOpusIdHeader / buildFormat and in
AudioTrackPlayer's MinBufferSize / 250 ms target / setSampleRate
calls. For Opus this is benign in practice — Codec2 always emits
48 kHz PCM regardless of OpusHead inputSampleRate — but hardcoding
the constant means a future codec or container variant whose
decoder DOES respect input sample rate would mis-clock playback.
And the OpusHead identification header should match what the
catalog declares either way.
Thread sampleRate alongside channelCount through every layer:
- MediaCodecOpusDecoder constructor takes
`sampleRate: Int = AudioFormat.SAMPLE_RATE_HZ`. buildFormat
and buildOpusIdHeader both take it as a parameter.
- AudioTrackPlayer constructor takes the same. Used in
AudioTrack.getMinBufferSize, the 250 ms-equivalent target
bytes calculation (`(sampleRate / 4) * BYTES_PER_SAMPLE *
channelCount`), AndroidAudioFormat.Builder.setSampleRate, and
the diagnostic log.
- decoderFactory and playerFactory in NestViewModel become
`(channelCount: Int, sampleRate: Int) -> ...`.
- awaitDecoderChannelCount → awaitAudioPipelineConfig, returning
a private `AudioPipelineConfig(channelCount, sampleRate)`
struct so openSubscription handles both fields uniformly.
`sampleRate` falls back to AudioFormat.SAMPLE_RATE_HZ on
timeout / non-positive declaration with a warning log.
- NestViewModelFactory + NestViewModelTest updated to the
two-arg factory shape.
G5: documented the SUBSCRIBE_BUFFER safety budget on
CATALOG_AWAIT_TIMEOUT_MS's kdoc. With the current 500 ms timeout +
SUBSCRIBE_BUFFER = 64-frame DROP_OLDEST flow + 50 fps Opus, at
most 25 frames buffer during the wait — leaving ≥ 39 frames of
margin (≈ 780 ms) before the oldest frame would be evicted. Even
at the production framesPerGroup = 50 (1 group/sec) cadence this
never trips during normal startup. No code change; just pinning
the rationale so a future timeout bump is checked against the
buffer size.
https://claude.ai/code/session_014JfZJHSTvyYYWJbC9VbB47
Claude
8a49486b37