Nice one Raff, Archiving your post.
Yesterday, encoded MP4 @ Aspect Ratio 240:1, was a bit of a struggle to re-AR @ 2.40:1
Is there a standard ffmpeg fix for that (there is a special ffmpeg version that re-does AR, somewhere on site).
(I used YAMB + MeGUI, about 6 tries to get correct).
EDIT: Some links on changing AR
http://forum.doom9.org/showthread.php?t=152419
http://forum.videohelp.com/threads/3...out-reencoding
http://forum.videohelp.com/threads/3...ut-re-encoding