<< IMHO avi file is an "uncompressed" format, the "compressed" file is in MPEG mpg format >>
AVI is an "Audio Video interleaved" file, which basically is a container object that contains a video file that can be uncompressed to very highly compressed.
MPEG is a standard(s) promoted by the "motion pictures entertainment group" which define its formats.
<< All consumer/prosumer video capture methods compress the video. Unless yer running with med/high end SCSI HDDs you can't even get smooth playback of uncompressed video on a computer.
>>
Actually, most consumer video capture cards support uncompressed video capture, I use it all the time. It is used for video mastering primarily certainly not for playback.