The 2020 session 'Author fragmented MPEG-4 content with AVAssetWriter' refers to the 2011 session 'Working with media in AVFoundation'
(and when I say 'refers', I mean it says 'I'm not going to cover this important part - just look at the 2011 video)
However - that session seems to be deleted/gone
Frustrating...
#wwdc20-10011
