The state of mainline hardware decoding

[CounterPillow]

New update: I've managed to seemingly get both vp8 and h264 decoding working with gstreamer. You'll need:

1. gst-build to build a git version of gstreamer and its plugins (you'll no longer need this once a new gstreamer release is cut and trickles down to distributions)
   
2. kernel 5.13 (might work with earlier kernels that also have the new uapi)
   
3. the libreELEC device tree changes linked above
   

It's worth noting that the obscure 10-bit H.264 profile decoding, for which rockchip are the only ones who provide a hardware decoder, is not yet possible.

The next step would be playing around with the ffmpeg patches to port them towards the new uapi and the latest ffmpeg version.