Great tutorial, the information on AV syncing is a little out of date. If the audio gets ahead of the video, then the video doesn't instantaneously skip to catch up, it continuously renders frames at full rate.

IIRC, I also don't think their mapping from SDL audio channels to ffmpeg channels is surjective (to say nothing of planar/non-planar audio).

I would suggest reading the ffplay.c example code.