The send loop was hardcoded to 960 samples (20ms/Opus24k), causing
DEGRADED (Opus 6k, 40ms) and CATASTROPHIC (Codec2 1200, 40ms) to
fail — the encoder needed 1920 samples but only got 960.
Changes:
- capture_buf, ring read threshold, and timestamp increment are now
computed from profile.frame_duration_ms (960 for 20ms, 1920 for 40ms)
- decode_buf sized to MAX_FRAME_SAMPLES (1920) to handle any incoming codec
- recv codec switch now uses correct QualityProfile per codec (was
inheriting original profile's frame_duration_ms, breaking cross-codec)
- added ComfortNoise guard on recv path
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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