Why doesn't lav video decoder use dxva2 with gpu?

Question

Windows

If the video card does not support hevc hardware decoding (but has hardware dxva2 support), then it will not decode through dxva2 either. And why?

Answer 1

DXVA is a GPU decoding acceleration interface. If the GPU does not know anything about H265, then it will not be able to decode it.
You can try choosing CUVID instead of DXVA. This is video decoding with CUDA.
I won’t tell you about AMD cards, because I haven’t worked with them.