Add hardware acceleration support for static files

[strig]

I'm using --device=/dev/dri:/dev/dri in my compose file but it doesn't seem to make any difference in CPU usage vs leaving it out. Am I missing some other config? Thanks

[m1k1o]

No, currently not implemented. Only for live transcoding. But should not be a big change to add it there.

[strig]

Gotcha, thanks. Might take a crack at it myself but don't know much about go or ffmpeg

[metal450]

Would also love to see this, for hardware transcoding of a static library hosted on Synology (https://timothybasanov.com/2018/12/08/hardware-accelerated-h264-encoding-synology-nas.html)