iMovie just supports such popular video formats as DV, HDV, MPEG-4, MPEG-2, MOV, and AVCHD.1. So if you have some video files can't import to imovie, you need use Video Converter for Mac to convert...
.torrent files are not "anything"-compatible. Their sole purpose is to instruct a BitTorrent client on what tracker to connect to to download the files you actually want. They contain very little...
If you burn Mp3s to a CD (Burn as DATA not Audio), then you will be able to fit far more music onto it.
Providing you have a CD player that can play back DATA CDs this will work much better for you...