The decode loop used to hold every access unit until its last wire
packet landed. With slice-progressive delivery (frame_parts) each newly
contiguous piece now goes straight into MediaCodec under
BUFFER_FLAG_PARTIAL_FRAME, the closing piece drops the flag, and the
decoder chews the front of the frame while its tail is still on the
wire.
Feeding partial input means owning its failure modes without a codec
flush: a broken sequence (dropped piece, orphan, oversize) closes the
dead AU with an empty non-partial buffer at its own pts, arms the
re-anchor freeze so the concealed output never reaches glass, and
requests a recovery keyframe - the same machinery ordinary loss already
rides. Per-AU accounting keeps its units: the RFI gap detector notes an
AU once, and the HUD stamps, host/network split and the phase-lock
arrival sensor ride only the completing delivery.
The opt-in is decoder truth and loop truth: every decoder this device
would use must pass FEATURE_PartialFrame, and only the async loop may
see parts - the legacy sync loop feeds whole AUs and stays that way.
Smoke-checked on-glass (NP3 vs the Windows host): byte-identical
degenerate path, presenter profile unchanged.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
enricobuehlerandClaude Fable 5
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