Plans the libopus 1.5.2 upgrade (audiopus → opusic-c/opusic-sys), DRED
enablement with tiered durations (100/200/500ms studio/normal/degraded),
removal of RaptorQ and Opus inband FEC from the Opus tiers, jitter buffer
lookahead/backfill refactor, and runtime escape hatch for rollout safety.
RaptorQ + current ratios preserved on Codec2 tiers (no DRED there).
Includes pre-flight verification findings: opusic-c Decoder inner pointer
is inaccessible (requires unified opusic-sys DecoderHandle), libopus 1.5
DRED API semantics clarified against xiph/opus opus.h, wire-format
backward compat verified on both live receive paths.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
09259cd6b8