AVI is audio video interleaved, I think, can't remember the MPEG one, but
the difference is, very quickly, AVI is a wrapper which can contain many
types of video, the most common being dv-avi - digital video avi, which
comes from digital camcorders. If you capture a dv-avi file asa dv-avi file
it will be exactly the same quality.
MPEG is a compressed file, an hour of dv-avi is 13gb, and hour of real good
quality mpeg2 is around 4gb. MPEG's are made up of I,Band P frames. Each I
frame is an actual frame, then in between the I frames you have "made up"
frames known as B or P frames. This is how you get the compression, it looks
to see what is similar and can then discard some info.
To edit a adv-avi you can cut it up at each and every frame, whereas with an
mpeg you can only cut it at an I frame, and these are often 12 frames apart.
You cna get compressed avi, the most usual is DIVX, and you can as you now
know get lots of mpegs, MPEG1/4 etc.
The main thing is to try to keep the quality as the best you can until you
come to the very final stage, so to make a dvd, you capture as dv-avi, edit
as dv-avi, output from that app as a dv-avi, then make a mpeg2 in the last
dvd authoring stage.
The other thing when working with mpegs is, if the app you use to make the
dvd does not recognise teh settings used to compress, or you can't tell it
not to compress compliant files, it will recompress your already compressed
file.
Hope this helps.
--
Graham Hughes
MVP Digital Media
www.myvideoproblems.co.uk
www.dvds2treasure.com
www.simplydv.com