claude-noether
6e8c970c1d
Iteration 2 of the campaign 8(+1)-phase loop opens following iter1
close (dc69378). Per phase0_evidence/2026-05-07/cross_validator_
traces.md suggested ordering, iter2 attacks HEVC Main on rkvdec —
the kernel + driver path is verified working (cross-validator sweep
exit 0); broken link is the libva backend at five distinct sites:
src/config.c HEVCMain case fall-through (analogous to iter1 Bug 1)
src/picture.c HEVCMain explicit UNSUPPORTED_PROFILE reject (NEW)
src/h265.c uncompiled in build (presumably staging-era CIDs;
Phase 2 source-read decides scope of rewrite)
include/hevc-ctrls.h staging-era local header (deferred from
iter1 Phase 5 Nit 6; iter2 closes the loop)
src/meson.build h265.c commented out (re-enable)
Plus possible novel issues vs iter1's MPEG-2 work:
- HEVC has 10 stateless control IDs vs MPEG-2's 3 (much larger
rewrite if h265.c uses staging-era API)
- HEVC slice_params is dynamic-array (kernel rkvdec accepts up
to 600 entries) — different submission shape vs MPEG-2 single-
struct or H.264 fixed-shape
- HEVC SCALING_MATRIX is conditional (only when scaling_list_
enabled in SPS); mapping VAIQMatrixBufferHEVC to V4L2 control
- HEVC ENTRY_POINT_OFFSETS is in kernel surface (tile/slice
resync) but campaign fixture doesn't use tiles — defer
Locked research question:
Make HEVC Main the third codec to pass boolean-correctness on
fresnel via libva-v4l2-request-fourier — mpv --hwdec=vaapi
bbb_720p10s_hevc.mp4 engages backend cleanly and DMA-BUF GL
import yields HW pixels byte-identical to SW reference for the
same frames.
Phase 1 success criterion (5 boolean checks, all must pass):
1. vainfo enumerates VAProfileHEVCMain on rkvdec env binding
(regression check; already passes today).
2. vaCreateConfig(VAProfileHEVCMain, VLD) returns VA_STATUS_
SUCCESS. (Pre-iter2: VA_STATUS_ERROR_UNSUPPORTED_PROFILE.)
3. ffmpeg -hwaccel vaapi -i bbb_720p10s_hevc.mp4 -frames:v 5
-f null - exits 0 cleanly with no Failed-to-create-decode-
configuration lines and no S_EXT_CTRLS EINVAL on HEVC
controls. (Phase 1 criterion 3 anchored on ffmpeg-direct,
mirroring iter1 Phase 5 Q4 amendment for codecs mpv may
filter out.)
4. mpv --hwdec=vaapi --vo=image at +02s seek: 2 distinct frames
hash-equal to SW reference, hash-differ from each other (real
motion). DMA-BUF GL import path per memory feedback_rockchip_
pixel_verify_path.md (NOT ffmpeg-vaapi+hwdownload, which is
cache-stale on RK3399 for both H.264 and MPEG-2 per iter1
Phase 6/7 findings).
5. iter1 MPEG-2 + T4 H.264 reference hashes BOTH still match
(regression check on prior-iteration cells):
MPEG-2 +02s: HW1=6e7873030dbf... HW2=ccc7ce08810d...
H.264 +30s: HW1=f623d5f7a416... HW2=7d7bc6f2146d...
Substrate carry-over:
- libva-v4l2-request-fourier master tip post-iter1-close
(commits e7dad7a..229d6d1 stack on iter8 65969da).
- bbb_720p10s_hevc.mp4 fixture (620 KB, HEVC Main, 1280x720,
24fps, 10s, yuv420p; provenance phase0_evidence/2026-05-07/
test_fixtures.md).
- Cross-validator anchor: phase0_evidence/2026-05-07/
cross_validator/hevc/ — 14 S_EXT_CTRLS + 5 QUERY_EXT_CTRL
(HEVC slice_params dynamic-array introspection unique among
the 5 codecs) + 4 REQUEST_ALLOC.
- Memory carries forward: feedback_gitea_as_claude_noether,
feedback_no_session_termination_attempts, feedback_header_
deletion_check (iter1 lesson L1 — apply to hevc-ctrls.h
deletion), feedback_review_empirical_over_theoretical
(iter1 lesson L2 — apply to Phase 5 review responses),
feedback_rockchip_pixel_verify_path (iter1 lesson L3 —
DMA-BUF GL is the verifier, NOT cached-mmap).
Out-of-scope (LOCKED): VP9/VP8 (later iterations); HEVC Main 10
(silicon support unverified); HEVC Main Still Picture; performance
metrics; long-duration HEVC stress; tile / wavefront parallel
processing (ENTRY_POINT_OFFSETS); Phase 4 cross-cutting backlog
(B1 device-discovery, B3 BeginPicture profile-aware reset, B4
context.c log suppression, B5 vbv_buffer_size negotiation, L3
vaDeriveImage cache-stale fix); chromium-fourier 149 install;
src/context.c changes; upstream engagement.
Predecessor open questions:
- iter1 B3 latent surface-reuse bug (picture.c:287
h264.matrix_set=false hits union byte 240) — for HEVC, the
union member is params.h265.{picture,slice,iqmatrix,
iqmatrix_set}. params.h265 layout differs from params.mpeg2.
Phase 2 source-read action item: verify whether byte 240 lands
in a meaningful HEVC field. If so, iter2 may need to address
even though MPEG-2 didn't.
Phase 2 source-read targets (queued for next phase):
- src/h265.c (~267 lines) — current state, target API
- src/picture.c:204-206 (the explicit HEVC reject)
- src/config.c:55-69 (confirm HEVCMain fall-through)
- src/surface.h:103-108 (params.h265 struct)
- include/hevc-ctrls.h (staging-era; identify CID/struct refs)
- src/meson.build (commented-out h265.c)
- linux/v4l2-controls.h:2110+ (modern HEVC stateless UAPI)
- drivers/staging/media/rkvdec/rkvdec_hevc.c (rkvdec contract)
- libavcodec/v4l2_request_hevc.c (FFmpeg reference impl)
- va/va_dec_hevc.h (VAAPI HEVC buffer structs)
Predicted iter2 close shape: similar pattern to iter1 (config
break + h265.c new-API rewrite + header delete + meson re-enable
+ picture.c reject removal). Larger code change than iter1
(predicting 250-400 lines for h265.c rewrite vs iter1's ~120 lines
for mpeg2.c). One novel construct (slice_params dynamic-array)
worth Phase 4 contract-clause-level attention. Expect Phase 6
takes longer than iter1; Phase 7 harness re-uses iter1's pattern.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
fresnel-fourier
TL;DR
Peer campaign to libva-multiplanar, targeting fresnel (Pinebook Pro / Rockchip RK3399) instead of ohm (PineTab2 / RK3566). Same deliverable shape — make libva-v4l2-request-fourier work end-to-end, for production VA-API consumers — but on a different SoC with a different (and broader) V4L2 decoder surface.
The libva backend fork itself (libva-v4l2-request-fourier) is shared: it lives at ../libva-multiplanar/libva-v4l2-request-fourier/. This campaign does not nest a second copy. Code-side work that turns out to be RK3399-specific lands either as #ifdef/runtime-detected paths inside that fork's master or, if scope diverges sharply, on a feature branch — Phase 2 source-read of each iteration decides.
Origin
libva-multiplanar reached iter5-close on 2026-05-05 with the ohm path solid: hantro (rk3568-vpu DT compatible) decodes H.264 to NV12 dmabufs end-to-end, three iterations of bugs fixed, mpv --hwdec=vaapi smooth, firefox-fourier RDD-sandboxed Firefox engages the backend without MOZ_DISABLE_RDD_SANDBOX=1, chromium-fourier 149 confirmed as the regression-check consumer.
That campaign's README explicitly names fresnel (RK3399) and ampere/boltzmann (RK3588) as "future iterations after ohm path is solid" (libva-multiplanar/README.md:87). fresnel-fourier is the formal peer campaign for the RK3399 leg of that promise.
Topology choice (LOCKED 2026-05-07): peer campaign, not child of libva-multiplanar. Each runs its own 8(+1) phase loop. Cross-link only — fresnel-fourier results do not gate libva-multiplanar's Phase 8 close (which already happened iteration-by-iteration on ohm).
Hardware target
fresnel — Pinebook Pro laptop. See reference_fresnel_kernel_constraints.md for the custom-OC-kernel discipline (don't let pacman -Syu clobber the OC DTB) and project_fresnel.md for fleet placement.
| Property | Value |
|---|---|
| SoC | Rockchip RK3399 (2× Cortex-A72 + 4× Cortex-A53) |
| GPU | Mali-T860 MP4 (Midgard, panfrost) |
| Decoder block 1 | rkvdec (/dev/video3) — H.264 + HEVC + VP9 |
| Decoder block 2 | hantro-vpu-dec (rk3399-vpu-dec, /dev/video5) — MPEG-2 + VP8 (RK3399 hantro does not advertise H.264; corrected 2026-05-07 from empirical V4L2 enumeration — see phase0_evidence/2026-05-07/v4l2_inventory_findings.md) |
| Encoder block | hantro-vpu-enc (/dev/video4) — JPEG only |
| OS | EndeavourOS-ARM (Arch derivative; same pacman + marfrit-packages mechanism as ohm) |
| Kernel | linux-eos-arm 6.19.9-99 — CONFIG_FTRACE=y, CONFIG_FUNCTION_TRACER=y, CONFIG_DYNAMIC_FTRACE=y, CONFIG_TRACING=y verified 2026-05-07. No rebuild needed for trace work. |
The decode-side surface area is genuinely broader than ohm. ohm has hantro (H.264 + MPEG-2 + VP8) and an rkvdec block whose mainline rkvdec2/vdpu346 driver isn't merged. fresnel has hantro (MPEG-2 + VP8 only — empirical, see correction note in the table above) plus a fully-driven mainline rkvdec covering H.264 + HEVC + VP9. So this campaign exercises codecs (HEVC, VP9) the libva-v4l2-request-fourier fork has never run on real hardware to date, and there is exactly one decoder bind for H.264 (rkvdec) — no two-block routing decision.
GPU side: panfrost on Mali-T860 (Midgard) is a different generation than ohm's Mali-G52 (Bifrost). KWin / Mesa / panfrost stack regressions or wins on T860 are not assumed to track G52 — the kwin-fourier verdict from fourier_attribution doesn't transfer for free.
Scope (LOCKED 2026-05-07 in phase0_findings.md)
In scope:
- libva-v4l2-request-fourier backend exercised on fresnel V4L2 decode nodes (
rkvdec+hantro-vpu-dec). - Codecs: everything decode-capable — H.264 + HEVC + VP9 (via rkvdec) + MPEG-2 + VP8 (via hantro-vpu-dec). This is the explicit broadening from libva-multiplanar's H.264-first locked scope.
- Test consumers:
vainfo,mpv --hwdec=vaapi, Firefox viamedia.ffmpeg.vaapi.enabled, chromium-fourier 149 (regression check). - Phase 1 success criterion (matching libva-multiplanar): boolean correctness — "libva accepted + providing access to hardware decoder for each codec." Performance metrics deferred.
- Phase 0 task 1: recover fresnel from the SDDM greeter crash-loop (per
~/.claude/plans/dynamic-forging-piglet.md). Recovery is bookkept as substrate work inside this campaign, not as a separate prereq.
Out of scope:
- Front-end libva (API library). Backend only.
- Other hardware (ohm + ampere/boltzmann are libva-multiplanar's iterations).
- AV1 (no decoder block on RK3399 supports it).
- Performance metrics — fresnel CPU/GPU benchmarking is a separate iteration after correctness lands.
cros-codecsRust replacement (peruser_stance_rust.md).- Bootlin / Collabora upstreaming default-deferred (per
feedback_no_upstream.md). Same discipline as libva-multiplanar. - KWin / panfrost / Mali-T860 work — orthogonal until proven otherwise; a parallel
kwin-fourier-fresnelcampaign would be a separate decision.
Process
8(+1) phase loop per feedback_dev_process.md. Phase 0 substrate is in phase0_findings.md. Phase 5 review uses the sonnet-architect subagent pattern (Plan with model: sonnet).
In-session-acquired data discipline per feedback_replicate_baseline_first.md: libva-multiplanar's ohm-side measurements are reference history, not threshold sources for fresnel-fourier cells.
Predecessor work this campaign builds on
../libva-multiplanar/— five closed iterations on ohm. Read in order:README.md— current state, codec scope, file map.phase8_iteration5_close.md— most recent close. The iter5-end backend is the substrate fresnel-fourier starts from.phase0_findings.md(andphase0_findings_iter[2-5].md) — locked-scope precedent for codec breadth and consumer matrix on ohm; useful frame-of-reference when locking fresnel-side scope.phase8_iteration1_close.md— iter1 surface-export DMA-BUF lifecycle race + multi-resolution cache + 64-pitch alignment bugs. Likely re-surface candidates on RK3399.
../libva-multiplanar/libva-v4l2-request-fourier/— the fork itself. 12 commits ahead of bootlin tip plus iter1..iter5 work.git logfor the actual landing record.~/.claude/plans/dynamic-forging-piglet.md— fresnel SDDM greeter crash diagnosis + recovery plan. Phase 0 task 1 picks up from here.~/src/fourier_attribution/— ohm-only attribution matrix. The chromium-fourier WHEAT-but-fragile verdict and Cell E (vanilla Chromium 149 control) item are ohm-side context, not fresnel data.
External reference (carry-over from libva-multiplanar):
- Mozilla bug 1833354 / 1965646 (Firefox HW decode on RK35xx via libva-v4l2-request).
- Bootlin upstream
bootlin/libva-v4l2-request— dormant since 2021. - Linux kernel
drivers/staging/media/rkvdec/— RK3399 rkvdec H.264/HEVC/VP9 control protocol reference. - Linux kernel
drivers/media/platform/verisilicon/hantro_*— RK3399-vpu-dec MPEG-2/H.264/VP8 control protocol reference.
Repository layout
~/src/fresnel-fourier/ <- this campaign (its own git repo)
├── README.md <- this file
├── phase0_findings.md <- locked research question + Phase 0 work list
├── (worklist.md, phase[2-8]*.md as phases land)
└── (the libva fork is NOT here — see ../libva-multiplanar/libva-v4l2-request-fourier/)
The campaign repo and the fork repo stay separate. fresnel-fourier commits its findings here; code changes to the backend land on the fork's master (or a branch named per the iteration if scope diverges from libva-multiplanar's ohm-side master).
Operator-facing repo URL: git.reauktion.de/marfrit/fresnel-fourier — created empty during scaffolding, no push until first iteration finds something worth publishing.
Non-upstreaming default
Inherited from libva-multiplanar / feedback_no_upstream.md. Patches must be aligned to upstream in syntax and semantics; PR/MR/bug-report only on explicit operator instruction.
Build infrastructure
distcc/cross-build path is the existing fleet: aarch64crosscompiler LXD on data, tesla LXD on hertz, dcc1 on dcw3. See reference_distcc_kernel_builds.md for invocation. Per the locked Phase 0 answer for libva-multiplanar (item 9), no distcc for libva builds — libva is small and links fast, hand-build on fresnel directly. Same default applies here unless a specific reason emerges.
For chromium-fourier 149 / firefox-fourier rebuilds against fresnel-side findings, the boltzmann LXD container path from libva-multiplanar iter3 is reusable.