Additionally, though, MP3 files don't loop properly. As far as I know, every major MP3 exporter will add a "frame" (.026 seconds) of blank audio at the beginning and end of the file. It's just enough to cause a seamless loop to fail.
There are ways to remove it, but it's tricky. The program I used was only able to remove most of it.
Yes, I'm a little bored. Good grief, posting this many barely-useful posts in the same day.... XD
What program do you use? I use Wavepad. It seems to be a good editor.
I use Audacity, with the LAME mp3 encoder. The program doesn't matter, though. It's the codec that matters.
To test it, export an mp3 file that has sound at the very beginning. Load the mp3 into a new document, Zoom in, and you'll probably see 0.026 seconds of nothing at the beginning.