Very useful list at
http://wiki.multimedia.cx/index.php?title=QuickTime_container
Particularly the parts about "elst" edit lists with regards to iPhone video.
Function: edit list
Contained In: edts
Can Contain: leaf atom
The elst atom contains the edit list. The edit list contains information about the times and durations that pieces of a media track are to be presented during playback. There are many Quicktime file decoders that choose to ignore this atom. This is not a good idea. The edit list atom must be taken into account to guarantee proper A/V sync on certain files.