marfrit 56abe3d6a2 iter4 Phase 3: VP9 baseline + 4-codec regression on 7.0 substrate ...

Captured on linux-fresnel-fourier 7.0-1 (post 6.19 decommission).

VP9 baseline (kernel-direct via ffmpeg-v4l2request on rkvdec):
- 5-frame SW reference PNG SHA256 anchors (criterion-4)
- VIDIOC_S_EXT_CTRLS strace with full payload at -s 16384
- Empirical struct sizes 168 B (FRAME) / 2040 B (COMPRESSED_HDR)
  supersede Phase 2 estimates of 144 / 1947
- Probe pattern: count=1 (FRAME-only) then count=2 (FRAME + COMPRESSED_HDR)

Phase 2 doc fix: control IDs corrected 0xa40b2c/d -> 0xa40a2c/d.

4-codec regression (H.264, MPEG-2, HEVC, VP8): all fall back to SW on
default config because /dev/video0 is now rockchip-rga (RGB color
converter), not a codec device. Fork hardcodes /dev/video0 in
request.c:149. Env override LIBVA_V4L2_REQUEST_VIDEO_PATH /
_MEDIA_PATH restores per-driver profile enumeration; mitigation A/B/C
queued for user decision.

New contract clauses surfaced:
- Clause 11: uncompressed-header partial parse for lf_delta /
  base_q_idx (VAAPI doesn't expose these; keyframe ref_deltas non-zero
  for BBB so leave-at-zero is wrong)
- Clause 12: compile-time sizeof asserts on the two control structs
  so future UAPI shifts fail loudly

iter4_phase3.tgz: full Phase 3 artifact bundle (strace + PNG refs).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

2026-05-09 20:31:53 +00:00

8.0 MiB

Raw History

View Raw