bece7b7016ee2206197e1468837666ef49df6002
1 Commits
| Author | SHA1 | Message | Date | |
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 claude-noether
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d5d4beb64d |
iter3 Phase 8 close: 4/5 codecs passing, 3 new memory entries
distilled, 0 Phase 7 → Phase 4 loopbacks
iter3 = VP8 on hantro-vpu-dec via libva-v4l2-request-fourier on
RK3399 (fresnel / Pinebook Pro). Fourth codec to ship.
Final state:
Fork tip: e1aca9c (post iter2 close 8d71e20 + 4 commits)
Phase 1 criteria: 5/5 GREEN (4 direct + 1 transitive)
LOC delta: +373 across 7 files (2 new + 5 modified)
Phase 7 → Phase 4 loopbacks: 0
Phase 6 fix-forwards: 1 (Commit D buffer.c allow-list)
Phase 5 review findings: 4 Critical, all empirically validated
Lessons distilled to memory (3 NEW entries):
feedback_hw_decode_engagement_check.md
Mandatory HW engagement check before claiming criterion-4
HW=SW PASS. mpv silently falls back to SW for some codec/
backend combos. Use lsof/strace/mpv -v/ffmpeg log to verify
HW path actually engaged. Established by user catch
mid-Phase-7: initial criterion-4 PASS was vacuous SW=SW.
reference_dmabuf_resv_blocker.md
Cross-campaign blocker. RK3399 hantro CAPTURE → libva
readback returns all-zero pages (videobuf2 missing
dma_resv release fence + panfrost no IOMMU_CACHE).
Tracked at git.reauktion.de/marfrit/dmabuf-modifier-triage/
issues/2. vb2_dma_resv kernel patches in flight (RFC v2,
2026-04 linux-media). Use transitive proof until patches
land: backend payload == kernel-direct payload AND
kernel-direct decode == SW reference.
feedback_runtime_enumerates_allowlists.md
Sibling to feedback_header_deletion_check.md. When ADDING
new enum values (buffer types, profiles, ioctls), grep
misses switch-default-rejection sites. Runtime enumerates
authoritatively — let fix-forward catch what grep missed.
Established by Phase 6 Commit D fix-forward: Phase 2 source-
read claimed buffer.c was type-agnostic; runtime enumerated
the explicit allow-list switch on first vaCreateBuffer.
Phase 5 amendments empirically validated (all 4 Critical correct):
C1 first_part_header_bits = slice->macroblock_offset → 6550 ✓
C2 first_part_size = partition_size[0]+ceil(macroblock_offset/8)
→ 22742 ✓ (= 21923 + 819, exact match for Phase 3 anchor)
C3 VAProbabilityBufferType (not VAProbabilityDataBufferType)
→ compiled clean post-Commit-D
C4 (int8_t) cast (not (s8)) → compiled clean Commit B first try
Estimated savings without Phase 5 review: 2 Phase 6 compile-fail/
fix-forward cycles (C3 + C4) + 1 Phase 7 → Phase 4 loopback (C1
+ C2 hardware-DMA-offset bug, would have produced visible-but-
corrupt output). Actual cost with review: 1 fix-forward (Commit
D, +1 LOC, was a Phase 2 source-read miss outside Phase 5 scope).
Cross-cutting backlog updates:
iter3-Q1 first_part_header_bits → CLOSED by Phase 5 C1
iter3-flags-anomaly bit 0x40 → not iter3 scope; kernel ignores
iter3-criterion-4-readback → blocked on dmabuf-modifier-triage
iter1; transitive proof used
iter3-mpv-vp8-fallback → mpv 0.41.0 falls back to SW for VP8;
consumer-side, not backend; verify
via chrome-fourier when convenient
Inherited backlog (B1, B3, B4, B5, B6, L3) — no closures from
iter3.
Campaign scoreboard: 3/5 → 4/5 codecs passing.
H.264 | rkvdec | T4 | PASS direct
MPEG-2 | hantro | iter1 | PASS direct
HEVC | rkvdec | iter2 | PASS direct
VP8 | hantro | iter3 | PASS transitive (readback blocked)
VP9 | rkvdec | iter4 | PENDING
iter4 (VP9 on rkvdec) prediction: comparable scope to iter2 HEVC
(VP9 has compressed-header control + probability state).
~400-500 LOC, 3-4 commits + 1 fix-forward. mpv may engage HW for
VP9 (different from VP8 fallback) — verify at iter4 Phase 0.
Refs:
phase0_findings_iter3.md (Phase 1 lock)
phase2_iter3_situation.md (situation analysis)
phase3_iter3_baseline.md (verbatim payload anchors)
phase4_iter3_plan.md (10 contract clauses + Phase 5 amendments)
phase5_iter3_review.md (4 Critical, all validated correct)
phase7_iter3_verification.md (4 direct + 1 transitive PASS)
Fork commits 27d82e3 + 017e27f + 7f84bbb + e1aca9c
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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