Add support for high-res video.

[nolliag]

Summary

This PR adds support for playing high-res video (with audio) via the vlc and mpv players.

Details

YT started splitting high-res video and audio into separate streams some time ago. The only stream that typically combines the two is the low-res 360p phone-compatible stream.

This PR addresses issue #942, by leveraging the ability for mpv and vlc to accept separate audio and video streams as CLI parameters. (See separate note below for mplayer.)

This PR is a more general solution than thatonearchguy's #1284 PR, leveraging the current URL handling architecture.

Compatibility Note

While mplayer does provide support for loading and playing a separate audio file, mplayer will only load local files and does not support streaming from remote URLs. Due to this limitation, this PR leaves the default functionality untouched for mplayer (meaning it will only play the 360p streams).

Code Formatting Note

I followed the PEP-8 standards for most of the code except where that would conflict with the existing code formatting (long lines). I'm more than happy to adjust that (or anything else) based on feedback!

Testing

Testing was manual. I've been running these changes for the past few months on Linux.

These changes have also been tested on Windows and work for vlc and mpv.

I also verified that the download feature continues to work, although it is unlikely this change would have affected it as it uses the built-in yt-dlp download functionality via pafy.

Known Issues

Having run this for a couple months, I've noticed two occasions where mpv would play the video, but not the audio stream. This seems to have been due to a network failure when mpv attempted to retrieve the audio stream. Stopping the stream and restarting it fixed the problem in both cases.

[henkmet]

Why did you close this pr?