As you know AVI is a container format, not a specific type of file. When QuickTime opens an .AVI file, it checks to see which codecs were used to encode the audio and video tracks within it. For example, an .AVI file may contain a video track encoded in the Cinepak codec and an audio track encoded with the ALaw 2:1 codec. If both the audio and the video were compressed using a codec that QuickTime can use, the file will play normally. If the audio or video or both were created using codecs that QuickTime cannot use, you may see an error message.
A best way to convert AVI to QuickTime is to use a yet professional tool like Brorsoft Video Converter. I've used for years.
