These modifications are from Detlev Casanova from collabora, who is currently developing HW stateless video decoders drivers for rk3588 and rk3576 SoC's . Using his patch for linux and ffmpeg using v4l2 requests and my patches for ffmpeg_codec2, I was able to get 4k@25 fps - 8-bit, running( HEVC and h.264) but still yet to optimise it and need to add hw decoders for vp9, av1, vp8 etc. NOTE - This is a testing build and might cause kernel panics.