panfrost doesn't accelerate video decoding, for that in amlogic you need vdec. Work as been done, but I don't now what is the state now , @UniformBuffer in this
was able to make it work with kernel 5.7.15. I wasn't able to make it work with balbes image Ver 20200828 kernel 5.7.16 in my X96 air (S905x3)
Maybe some one can say some thing about the state of video hardware decoding.