[Cin] h264 vulkan encoding

[Andrea paz]

> Thank you. Setting this environment helped to remove the first error message
>
> export ANV_VIDEO_DECODE=1
> vulkaninfo | grep VK_KHR_video_decode_queue
>     VK_KHR_video_decode_queue                     : extension revision 8
>
> Still remaining hwaccel initialisation returned error for h264 and h265 input respectively:

Same for me (with AMD)