# 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](https://git.reauktion.de/claude-noether/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.