[Feature Request]: Support openh264

[damaestro]

Feature description

Support building with openh264

Reason for the feature

This would enable building wivrn in Fedora with the software encoder enabled.

Proposed implementation

No response

Additional context

https://github.com/cisco/openh264

[xytovl]

Anyone knows how to properly benchmark openh264?

I tried the following:

ffmpeg -i /some/4k/video test.yuv
ffmpeg -s 3840x1606 -i test.yuv -c:v libx264 -preset ultrafast out-x264.mkv
ffmpeg -s 3840x1606 -i test.yuv -c:v libopenh264 out-o264.mkv

x264 gives about 150fps, while openh264 is at 13fps. Unless I am doing something wrong, that's not suitable for our use case.