AV1 in hardware. Plaid Number Nine.

Install

1. Confirm you're on the BSP kernel

   The fix uses the RK3588 VPU, which needs the vendor BSP kernel.

   check

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   ls /dev/mpp_service   # must exist. "No such file" = mainline; guide doesn't apply.

2. Install the packaged VA-API driver

   Release 3.0.0 "Plaid Number Nine". Grab it from the release.

   bash

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   cd /tmp
   wget https://github.com/defcom5-rockchip/rockchip-vaapi/releases/download/v3.0.0/rockchip-vaapi_3.0.0-1_arm64.deb
   sudo apt install ./rockchip-vaapi_3.0.0-1_arm64.deb

   If apt says librga2 or librockchip-mpp1 is not installable, add your image's Rockchip multimedia repository first. Or download from the Releases page.

3. Use the real Firefox .deb, not the snap

   The snap build won't hardware-decode here — use the mozillateam PPA build if needed.

   check

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   firefox --version   # if it says "snap", switch to the .deb build

4. Turn on hardware decode

   Wrap Firefox so it always gets the two required env vars:

   /usr/local/bin/firefox-hw

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   sudo tee /usr/local/bin/firefox-hw >/dev/null <<'EOF'
   #!/bin/sh
   export LIBVA_DRIVER_NAME=rockchip
   export MOZ_DISABLE_RDD_SANDBOX=1
   exec /usr/bin/firefox "$@"
   EOF
   sudo chmod +x /usr/local/bin/firefox-hw

   Then set these in Firefox about:config:

   about:config

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   media.ffmpeg.vaapi.enabled                  = true
   media.hardware-video-decoding.enabled       = true
   media.hardware-video-decoding.force-enabled = true

5. Launch through the wrapper

   Run firefox-hw (or point your dock/menu shortcut at it). No logout needed — it sets the env every launch.

6. Verify AV1

   Play an AV1 title (YouTube serves most 4K as AV1; Stats for nerds shows av01…). Then:

   while it plays

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   vainfo | grep -E 'Driver version|AV1'   # 3.0.0 "Plaid Number Nine", VAProfileAV1Profile0
   grep av1d /proc/interrupts            # the AV1 engine's interrupt count climbs, one per frame
   sudo fuser /dev/mpp_service           # the browser's media process holds the decoder

7. Verify on the video that used to break (VP9)

   Play Simple Minds — Don't You (Forget About Me) at 2160p. Right-click → Stats for nerds: codec reads vp09… at 2970×2160@25 — the exact odd-width stream that used to render green.

   while it plays

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   sudo fuser /dev/mpp_service   # a Firefox RDD process, single-digit %CPU = real HW decode

Keep it on the fast path

mkdir -p ~/.local/share/applications
sed 's|^Exec=/usr/bin/firefox|Exec=env LIBVA_DRIVER_NAME=rockchip MOZ_DISABLE_RDD_SANDBOX=1 /usr/bin/firefox|' \
  /usr/share/applications/firefox.desktop > ~/.local/share/applications/firefox.desktop

What 3.0.0 adds

An AV1 OBU re-serialiser (src/av1.c with a vendored copy of GStreamer's AV1 bit writer, five bugs fixed in it and segmentation implemented). The one value VA-API never passes, refresh_frame_flags, is read from the next picture's reference map, so each picture is held until its successor arrives — or decoded at once when the player syncs it, with the slot refresh following as a hidden frame. Hidden frames are shown through a synthesised show_existing_frame; hidden key frames through a second decode as an intra-only frame. Details in DEVELOPMENT.md, limits in KNOWN-ISSUES KI-13.

What the 2.x VP9 fix was

The driver exported its NV12 surface at a 16-aligned stride. For a coded width that isn't a multiple of 16 (2970 → 2976), the RK3588 Mali/EGL DMA-BUF importer expects a 64-aligned pitch, so the chroma plane landed at the wrong offset → green. The fix aligns the export stride to 64 (2970 → 3008), matching the canonical Rockchip pattern.