avi mpg

auggybendoggy wrote on 9/17/2006, 7:36 PM

Guys,
When I use my 3d renderer (carrara 5) to creat an AVI it asks me about compression.

in the list is mpeg4 and I choose this. I thought an AVI was always uncompressed. If I am wrong then what is the difference in rendering an mpg2 vs a AVI mpg4 video?

Can someone educate me?

Auggy

Comments

ScottW wrote on 9/17/2006, 8:00 PM

AVI files are simply a container and can hold all manner of beastie; from uncompressed all the way up to very highly compressed information.

The difference in rendering MPEG2 vs. MPEG4 is the codec used and the underlying standard.

--Scott

auggybendoggy wrote on 9/18/2006, 4:44 PM

so does this mean a AVI can be an MPG compression?

Auggy

ScottW wrote on 9/18/2006, 4:48 PM

Yes. The AVI is simply a container. It could hold MPEG-1, MPEG-2 or MPEG-4, DV or any number of things. The very beginning of the data in the AVI file describes what is contained in the file. This is one of the reasons I find GSpot to be such a useful utility - it will tell you what's in the AVI file and then tell you if you have a codec installed on you machine that can handle it.

rmack350 wrote on 9/18/2006, 4:53 PM

Well, evidently an avi file can have mpeg4 compression (which is pretty different from mpeg1 and 2, I think).

I'd assume that with mpeg 1 and 2 you'd want the player to know it's got an mpeg file, rather than needing to use a player that understands AVI files. So you'd not render an AVI with mpeg2 compression. You'd render a straight mpeg2 file.

perhaps the answer is that, even if you could render an AVI file that way, it probably isn't very practical.

Rob Mack

auggybendoggy wrote on 9/18/2006, 8:53 PM

so what is mpeg 4 vs. mpeg2
is there any benefits to either?

Aug

Chienworks wrote on 9/19/2006, 3:26 AM

MPEG4 is a much denser and more efficient algorithm. You can get better quality at smaller files sizes than MPEG2 can produce. However, it would appear that the advantage is only useful at lower bitrates. MPEG4 is a good choice for web video or portable media players. At higher bitrates MPEG2 still seems preferable. Consider that MPEG4 was an established standard well before HD camcorders started shipping, yet HD uses MPEG2 instead of MPEG4.

So, if you're creating high quality, high bitrate files to be used for editing, choose MPEG2 instead of MPEG4.

farss wrote on 9/19/2006, 4:01 AM

Or most programs doing CGIish things can simply render a bmp sequence. Yes you end up with a LOT of BIG files but they go into Vegas as smooth as silk, composite perfectly, you can tweak them in PS using batching etc. Once you've got the sequence into Vegas you can render out to anything and delete the source files.
Well that's what I've been doing fiddling around with Bryce, couldn't see any point in waiting an hour for it to render a few hundred frames with so much work going into AA etc to then compress it into a lossy codec.