avi mpg differences

[venson]

Hi. I'm a newbie here, and in digital video too.

I'm getting confused with this matter. I mean, i know that the quallity of an avi file compressed with a good codec (let's say xvid) it's much better than a mpg file of the same bitrate, but what are really the differences betwin the two formats? And another think. the xvid codec is called as xvid mpeg4. Does it have any similarity with the mp4 format?

[celtic_druid]

XviD is MPEG-4 Part 2, mp4 is MPEG-4 Part 14. mp4 is the offical MPEG-4 container and MPEG-4 Part 2 is one of the offical MPEG-4 video formats.

avi, mpg and mp4 are all just containers. No reason why you can't put MPEG1/2 in an avi or mp4 container or why you can't put MPEG-4 in an mpeg ps/ts container. Makes more sense than avi really.