Was able to compile MPV for Steam Link hardware.

I would call this more proof of concept than a beta at this point.
You will want a keyboard to use this.

I wouldn't expect much so far. Currently it just plays a trailer from https://www.davestrailerpage.co.uk/ that's set up in the toc.txt file.

I'm not endorsing the gentlemen movie, I just picked one at random.

Video playback is pretty solid at 640x480 but isn't stretched fullscreen. I would assume there are options that will work better, but figured I'd kick this out and see if anyone has any scripts or other interesting ways to make this work better. You can hit F for fullscreen but it doesn't look right.

Streaming radio stations and mp3s are probably your best bet. I would imagine that any local movies are over 480p and it's likely going to suffer unless downsampled with ffmpeg or something.

Not endorsing this one either, but is a valid test. (Radio stream)
http://107.182.231.73:7170/

I did spend some time looking at youtube-dl but without python I think we'd need some other frontend. Minitube is promising and uses QT, but fails at x11extras due to version differences or something else. I'll keep working on a frontend for it.

I think your best bet for testing is to modify the toc.txt and overwrite it again via ftp. Once you start the program hit CTRL+C on a keyboard to quit and it will then update the icon with the new toc (clears the cache). Then just start it again to use your changes.

You can get the file here. Do the normal steamlink/apps usb install.
https://drive.google.com/open?id=1NURbX15gDMOB4nkaUf1d9dUCCDZ8qpVt