on_playback() was passing miniaudio's hardware playback-callback frame
count to opus_decode()'s max_samples, instead of the decoder's fixed
frame size (960 samples @ 20ms/48kHz). Since real packets decode to
more samples than the (often smaller, e.g. ~480 on default low-latency
WASAPI) hardware period, opus_decode returned OPUS_BUFFER_TOO_SMALL on
nearly every callback -- packets were received/decrypted/jitter-buffered
correctly but never decoded into audible PCM. Result: control-plane
events and VAD worked, but zero audio in headphones.
mix_for_test()'s white-box test masked this since it always called
on_playback with frames == frame_samples, the one case where the bug
is invisible.
Fix: RemoteStream gained a small ring buffer (init_ring/push_ring/
pop_ring) that decouples decode cadence from playback-callback cadence.
on_playback now tops the ring up by decoding whole Opus frames (always
decoder.frame_samples(), never the hardware frame count) and drains
exactly what the callback asks for, silence-padding (PLC) on underrun.
Side effect: also fixes playout_ts, which was advancing by the wrong
unit (hardware frames instead of decoded samples) -- it now tracks
correctly against jitter-buffer timestamps.
ctest --test-dir build/m1-dev: 12/12 green.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Talon
5be869c61a