Hi, good work there.
I know a fix for many of the A/V sync problems with youtube (when video stream play a little fast, audio is ok).
Is a mplayer little problem, not canola.
For some videos in flv container (youtube for example) mplayer needs the experimental parameter -correct-pts. It works in the last version of mplayer, maybe in the older one too.

Note: Some videos in youtube have true sync problems, this fix is only for the mplayer bug with some flv videos.

I don't know how to config atabake to add extra parameters to mplayer. But maybe this can help the Youtube Plugin team.