DV AVIs

[Tiffany]

Is there any difference between an AVI created from a composite input, and a DV AVI which may be created from composite input but converted to DV AVI via a firewire card and recorded to the harddrive (as used by the Canopus vidcap cards?

Is the captured DV AVI compressed (similar to MJPEG compression)?
Is there an improvement in the quality of the AVI?

Thanks in advance....