Here's my FFmpeg command for converting video files for the Innotab:
-s 480x272 -aspect 1.777 -vcodec mjpeg -b 1800k -r 15 -acodec pcm_s16le -ar 20050 -ac 1 -vol 512
I've modified it to make videos full screen on the Innotab. Although this may involve altering the aspect ratio quite a bit (the Innotab is wide screen), videos seem to be more watchable using all of the screen.
I've also added a volume boost because the audio channel can come out very quite. -vol 512 doubles the volume. The command goes up from zero boost in increments of 256: 256, 512, 768, 1024- but higher levels introduce a lot of distortion.
Incidentally, if Dora the Explorer needs a singing map to tell her that to get to the Library she must cross the troll bridge and climb a bigggg rock, how did she get the eight library books in the first place?