Watching videos on your mobile phone
On a motorola a835 in my case. This phone supports mp4 and 3gp playback (perhaps some other formats as well, but i’m fine with 3gp), which should work on most phones capable of video playback, e.g. the nokia 3650 and 6600, as well.
I use the nokia multimedia converter to convert my video files to 3gp format cause it’s simple to use and allows playing around with a lot of encoding settings for best results. You can grab the program for free @forum nokia (registration required for download). It’s only available for windows, but here’s a nice tutorial on how to use ffmpeg to encode 3gp videos under linux (already posted this to the linklog a while back). If you are on mac os x, quicktime might do the job, but i don’t know for sure.
Before i come to the settings i found to work best for my needs, a few words about the phone i’m gonna playback the files on: the moto a835 got a fairly decent display with a resolution of 176×220, but can’t playback video in fullscreen mode (at least i’m not aware how to do that), so the default qcif resolution of 176×144 works just fine. The phone has 64mb of internal memory and no memory card slots. That’s enough memory for a few episodes of your favourite sitcom. The limiting factor however is data transfer speed. I don’t know for sure what causes data transfer to be so painstakingly slow, but it takes approximately one minute to transfer 350kb - even with a usb cable. As a rule of thumb i wanted to get the size of one minute of converted video to 350kb - waiting 40 minutes to transfer 20 minutes of video was out of question for me. To achieve this i played around with the settings a bit and tested the results on my phone. During the process i made some interesting findings: changing resolution and fps had no considerable impact on the resulting file size, increasing intra period setting and lowering the bit rate of video enconding had.
The settings i found to work best for my needs aren’t radically different from the base settings, but here they are anyway:
video: qcif resolution (176×144), 15 fps, 30 seconds intra period, 36 kbps bit rate
audio: amr, 12,2 kbps bit rate
A side note: binary bonsai posted a link to a download archive of the star wars clone wars animated series today. I found those animated shorts to work surprisingly well for a few minutes of entertainment on the road.