Option to prefer multi-channel, and higher quality audio

[mzso]

Hi!

I found that some videos have multi channel audio now. I'm not sure by what logic are the tracks selected, or if they're selected at all, but I only see AAC streams for multi channel. And since the video codec is normally VP9, I expect it won't be selected by the youtube player in any way for me.

So an option to prefer multi-channel higher quality streams would be nice. I'm not sure wether these streams are only created for multi-channel or sometimes for stereo as well. In the latter case it might be useful for selection in any way because of higher quality.

Example video: https://www.youtube.com/watch?v=obOEEYSiA_w