MP4 to PSP unsupported data?

When I put videos on my PSP in mp4 format it shows up on the actual PSP BUT when I try to watch a video on the actual PSP it says Unsupported Data what am I doing wrong?

• Answer:

  'MP4' is a 'container' format, combining both audio and video information into one file. These separate 'streams' are themselves encoded, and there are many forms of compression they can use. The PSP can't always decode these streams - in short, not all files with the extension 'mp4' are made the same way. A file may play perfectly on a PC, but not the PSP because of this. What you need to do is use a program such as Super or PSP Video 9. You can run the mp4 file through it, and it can create another version of it specifically to work on the PSP.