Mono sound through a loud speaker tuned for low-quality telephone conversations doesn't do much to cooperate the idea of the mobile cinema. So in my search for the latter, I quickly realized that it was necessary to move the audio part of the experience away from the Nokia 3650 and onto something more suitable. Luckily, the answer was obvious: My iPod.
Using an iPod in conjunction with the phone requires a split of video and audio from the source material, which in my case is VCD/MPEG1-based TV series episodes. QuickTime with a pro key let's you turn the video track into 3GPP chunks (make sure to turn off the audio track) that'll take up between 10-14MB with a regular 20-30 minute show.
FFmpeg can isolate the audio track to 128bit MP3 from the command line with:
ffmpeg -vn -ab 128 -acodec mp3 -i inputMovie.mpg outputAudioTrack.mp3
This will generate a 20-30MB file, which in turn can be converted by iTunes to a AAC file of half the size — but that's unnecessary unless you're running low on space with the iPod.
With the video and audio tracks on separate devices, you'll need to do a bit of manual synchronization, though. But it's really quite easy. Try starting both at once (keep them paused at 00:00 and press both start keys at once). If you're a tad of in the timing, just do a little real-time pausing of one of the tracks until it catches up. With a bit of practice, it shouldn't take more than a few tries to have them synchronized.
Oh, and don't worry too much about battery time. I ran five episodes of Friends and five episodes of The Simpsons on a single charge yesterday and still had juice left over for two voice calls and some ten SMS' and about half a day of stand-by.
I'm investigating an AppleScripted workflow-solution that'll make the conversion and track splitting a case of drag'n'drop. If I get it working, I'll be sure to post it here.