claude-noether
9a71dbf4c3
Opens iter4 immediately after iter3 close (d5d4beb). Targets VP9
Profile 0 as the fifth (final) codec to pass boolean-correctness
on fresnel via libva-v4l2-request-fourier — completes the campaign
codec scope.
Locked research question:
mpv --hwdec=vaapi bbb_720p10s_vp9.webm engages backend cleanly
on rkvdec, and HW pixel readback yields byte-identical output
to a software-decoded reference for the same frames.
Five Phase 1 boolean criteria:
1. vainfo enumerates VAProfileVP9Profile0 on rkvdec env binding
2. vaCreateConfig(VAProfileVP9Profile0, VLD) = SUCCESS
3. ffmpeg -hwaccel vaapi VP9 5-frame decode exit 0
4. HW=SW byte-identical with HW engagement verified per memory
feedback_hw_decode_engagement_check.md (mpv -v log inspection
before claiming match). If mpv falls back to SW for VP9 like
it did for iter3 VP8, OR if rkvdec exhibits the same dma_resv
kernel issue as hantro, fall through to transitive proof per
memory reference_dmabuf_resv_blocker.md (libva backend
payload == kernel-direct payload AND kernel-direct decode ==
SW reference).
5. FOUR-codec regression block: H.264 + MPEG-2 + HEVC + VP8
reference hashes hold
Substrate carry-forward (re-verified):
- fork tip e1aca9c (post-iter3-close)
- /usr/lib/dri/v4l2_request_drv_video.so SHA256 0ab5b2ba...4ef
- linux-eos-arm 6.19.9-99-eos-arm
- bbb_720p10s_vp9.webm fixture on fresnel ~/fourier-test/ (3.4 MB)
- rkvdec OUTPUT_MPLANE VP9F + 2 VP9 stateless controls
(V4L2_CID_STATELESS_VP9_FRAME = 0xa40b2c, COMPRESSED_HDR =
0xa40b2d)
- cross-validator anchor confirmed: rkvdec advertises VP9 per
Phase 0 V4L2 inventory
- Reference sources local:
references/ffmpeg-kwiboo/libavcodec/v4l2_request_vp9.c
references/ffmpeg-kwiboo/libavcodec/vaapi_vp9.c
references/linux-mainline/drivers/staging/media/rkvdec/
rkvdec-vp9.c (verify presence at Phase 2)
Predicted scope:
- config.c: ADD VP9 enumeration block + RequestCreateConfig case
+ RequestQueryConfigEntrypoints case (3 sites; same shape as
iter3 VP8)
- src/vp9.c NEW file (~250-350 LOC; 2 V4L2 controls per frame:
FRAME + COMPRESSED_HDR; 8-entry DPB vs VP8's 3)
- src/vp9.h NEW file
- src/meson.build add 'vp9.c' + 'vp9.h' entries
- picture.c codec_set_controls VP9 dispatch + codec_store_buffer
cases for 2 VAAPI VP9 buffer types (Picture + Slice; NO
Probability + IQMatrix unlike iter3 VP8)
- surface.h params union extend with vp9 member
- context.c: NO changes expected (no init-time menus per FFmpeg
ref pattern)
- buffer.c: predicted no Commit D needed (VP9 uses Picture +
Slice + SliceData buffer types — all already whitelisted by
H.264 path); plan for fix-forward if runtime miss surfaces
per memory feedback_runtime_enumerates_allowlists.md
Predicted total: ~400-500 LOC, 3-4 commits + 0-1 fix-forwards.
Larger than iter3 VP8 (370 LOC) but comparable to iter2 HEVC
(470 LOC).
VP9 contract surface:
- 2 controls per frame batched in single S_EXT_CTRLS:
FRAME (struct v4l2_ctrl_vp9_frame) + COMPRESSED_HDR
(struct v4l2_ctrl_vp9_compressed_hdr — probability updates
from compressed header)
- 8 reference frames in DPB (active_ref_frames[8])
- Tile-based decoding (VP9 has 1..N tiles per frame)
- Profile 0 only (8-bit 4:2:0); Profile 1/2/3 OUT-OF-SCOPE
Phase 2 source-read targets queued: config.c enumeration pattern,
picture.c dispatch + per-buffer-type cases, surface.h params union,
VAAPI <va/va_dec_vp9.h>, kernel UAPI v4l2_ctrl_vp9_frame +
v4l2_ctrl_vp9_compressed_hdr (lines 2696-2870), kernel rkvdec-
vp9.c driver, FFmpeg v4l2_request_vp9.c + vaapi_vp9.c.
Memory carry-forward (all 9 entries apply unchanged):
feedback_gitea_as_claude_noether
feedback_no_session_termination_attempts
feedback_header_deletion_check
feedback_runtime_enumerates_allowlists (NEW iter3)
feedback_review_empirical_over_theoretical (BOTH directions)
feedback_rockchip_pixel_verify_path
feedback_fresnel_hostname (NEW iter3)
feedback_hw_decode_engagement_check (NEW iter3)
reference_dmabuf_resv_blocker (NEW iter3)
Open questions inherited from iter3 close (not blocking iter4
lock):
- Does mpv 0.41.0 engage HW for VP9 hwdec=vaapi or fall back
like it did for VP8? Phase 0+3 verifies via mpv -v log.
- Does rkvdec exhibit the same vb2_dma_resv kernel issue as
hantro? Likely no (different driver subsystem; iter1+iter2
mpv-DMA-BUF-GL paths worked on rkvdec). Phase 3 baseline
answers via ffmpeg-vaapi-hwdownload non-zero check.
iter4 = final codec in campaign scope. Clean close → 5/5 codecs
passing → campaign complete.
Refs:
phase0_findings_iter1.md (iter1 MPEG-2 lock template)
phase0_findings_iter2.md (iter2 HEVC lock template)
phase0_findings_iter3.md (iter3 VP8 lock template)
phase8_iteration3_close.md (immediate predecessor close)
phase0_evidence/2026-05-07/v4l2_inventory_findings.md (rkvdec
VP9 capability)
phase0_evidence/2026-05-07/test_fixtures.md (bbb_720p10s_vp9.
webm provenance)
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.