Empirical strace of all 5 codecs through libva shows VIDIOC_S_FMT on
OUTPUT_MPLANE ships pixelformat V4L2_PIX_FMT_H264_SLICE for EVERY
profile. HEVC controls submitted on H264_SLICE OUTPUT → kernel rkvdec
silently rejects/no-ops → CAPTURE stays in cap_pool init (all-zero).
Per-codec Bug 2 taxonomy:
- HEVC, VP9, VP8: OUTPUT format mismatch on rkvdec/hantro-strict → 100% zero
- MPEG-2: format mismatch but hantro tolerates → works
- H.264: format right by coincidence; keyframe decodes, inter all-zero
(Bug 4, separate, deferred from iter5b)
Site: src/surface.c:173 `unsigned int pixelformat = V4L2_PIX_FMT_H264_SLICE`.
Same bug class as feedback_unconditional_codec_state.md
(iter4 h264_start_code = true).
iter5b new Phase 1: fix surface.c to switch pixelformat on
config_object->profile. 4 criteria locked, all backend-side, no kernel
patches. RFC v2 series filed back to backlog for a future
DMABUF-import-consumer campaign.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
