feature request: improve compatibility with youtube thumbnails for music tunnel

[reds7one]

currently, when using music tunnel with YouTube videos, the central image is a version of the YouTube thumbnail that is squished into a square.

I do not know how easy this is to change, but I would appreciate it if you could change the code so that it is not squished

also, a secondary request that seem so difficult that you should probably just ignore it: make the tunnel background be the video as it plays