However, most, if not all AVI playback issues arise with movies that have been compressed using CODECs (Compressor - Decompressor) that are unavailable for QuickTime in Mac OS X. AVI was originally called Video for Windows ® (VFW) and QuickTime supports the VFW format. AVI is a media container very similar to QuickTime, but with a unique data format. There has been confusion over AVI files since QuickTime ® added support for such.
This chapter from our book Troubleshooting Mac® OS X discusses why some Audio Video Interleaved (AVI) multimedia files do not play in QuickTime and provides methods for playing AVIs on Mac OS X.