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claude-noether f9562972bd Phase 0: AV1 hw decode on ampere VERIFIED bit-perfect first-try

Pivoted from ampere-vp9-enablement (closed at structural impossibility
on rkvdec/vdpu381). Janet PIVOT verdict pointed at AV1 — verification
shows it works out-of-the-box on mainline 7.0.0-rc3:

- Kernel driver: drivers/media/platform/verisilicon/
  rockchip_vpu981_hw_av1_dec.c (in-tree, loaded as hantro-vpu)
- Hardware: vpu981 dedicated AV1 IP at fdc70000 (separate from rkvdec)
- V4L2 node: /dev/video4 enumerates AV1F format
- Userspace: ffmpeg -hwaccel v4l2request kdirect path works

Verification: byte-compare HW (hantro-vpu) vs SW (libdav1d) on two
AOM test vectors:
  - av1-1-b8-01-size-208x208.ivf  (2 frames):  100.0000% exact match
  - av1-1-b8-23-film_grain-50.ivf (10 frames): 100.0000% exact match
    per frame, including AV1 film_grain post-processing

Pivot outcome:
- VP9 campaign: 10 iterations + 2 architect reviews → structural
  impossibility (kernel-side gap that needs upstream/Collabora coord)
- AV1 verification: 0 iterations → bit-perfect first try

The "enablement campaign" framing is mostly inappropriate for AV1 —
this is a verification campaign. Real upstream work was done by
Verisilicon + Collabora; we just confirm it works on ampere.

Optional follow-ups (out of Phase 0 scope):
A. libva backend AV1 dispatch (enables VAAPI consumers)
B. Fluster AV1-TEST-VECTORS comprehensive validation
C. 1080p/4K real-world AV1 stress test

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

2026-05-17 07:00:02 +00:00

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ampere-av1-enablement

AV1 hardware decode verification on Rockchip RK3588 ampere (CoolPi CM5 GenBook).

Status (2026-05-17 09:00)

VERIFIED WORKING bit-perfect first-try using mainline 7.0.0-rc3 + ffmpeg-v4l2request kdirect path on the hantro vpu981 AV1 driver. Zero new code required.

Sibling campaign ampere-vp9-enablement closed at structural-impossibility on rkvdec/vdpu381 VP9; Janet PIVOT verdict pointed to AV1; verification confirmed AV1 works out-of-the-box.

Verification

$ ssh ampere
$ ffmpeg -hwaccel v4l2request -hwaccel_output_format drm_prime \
    -i /tmp/av1_larger.ivf -vf 'hwdownload,format=nv12' \
    -f rawvideo -pix_fmt nv12 /tmp/hw-av1-all.nv12
[AVHWFramesContext] Using V4L2 media driver hantro-vpu (7.0.0) for AV1F

Byte-compare against ffmpeg's libdav1d SW reference, all 10 frames of the av1-1-b8-23-film_grain-50.ivf test vector (352×288, includes film-grain feature):

frame 0: exact=100.0000%
frame 1: exact=100.0000%
... 
frame 9: exact=100.0000%

Smaller test vector (av1-1-b8-01-size-208x208.ivf, 2 frames): also 100% match.

Driver stack

IP: vpu981 (Rockchip's dedicated AV1 hardware on RK3588, MMIO at fdc70000)
Kernel driver: drivers/media/platform/verisilicon/rockchip_vpu981_hw_av1_dec.c (in-tree)
DT compatible: presumably rockchip,rk3588-vpu981-av1-dec (verified loaded via lsmod | grep hantro_vpu)
V4L2 node: /dev/video4 (enumerates AV1F format)
Userspace path: ffmpeg -hwaccel v4l2request (kdirect, not libva)

What's NOT done

libva-v4l2-request-fourier backend AV1 dispatch — backend has no AV1 codec module. ffmpeg-v4l2request kdirect works without libva. Adding libva AV1 support would make AV1 available to other VAAPI consumers (VLC, mpv with VA-API, GStreamer-VAAPI, browsers via VAAPI/VDPAU). Estimated effort: 1-2 days mirroring the existing HEVC/H.264/VP9 dispatch patterns in ~/src/libva-v4l2-request-fourier/src/ (sibling repo).
Fluster AV1-TEST-VECTORS comprehensive validation (only ran 2 of the AOM test vectors).
Stress test (long bitstream, 1080p+, complex features beyond film_grain).

Out of scope

Adding AV1 to rkvdec/vdpu381 (would duplicate the working hantro-vpu981 path)
Reviving the failed VP9 work from sibling campaign

Process

This is a verification campaign more than an enablement campaign. The work was done upstream by Verisilicon + Collabora; this repo documents that it works on ampere out-of-the-box.

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