The word is MPeg 4 types are going to be used for DVD for the HD-DVD or Blu-ray Disc format dvd's instead of MPeg 2. I believe the fore-runner for this is H.264 format. Not DivX format which is a highly protected/copyright/patent format. DivX format is not as advanced in abilities as H.264 format potential. More about H.264 format here http://en.wikipedia.org/wiki/H.264
More about MPeg 4 formats here: http://en.wikipedia.org/wiki/MPEG_4
More about DivX here http://en.wikipedia.org/wiki/Divx

AVI can be almost any format. It can be divx or xvid, Cinepak, Indeo video, Matroska, etc. AVI is just the outer shell if you like. QuickTime is also very similar. A QT file could be any no. of formats.

Some of the newer dvd players can now play mpeg4/divx. Mine can & it's very handy just burning a data dvd to play the files rather than converting to mpeg 2. So much more can fit on. A 700 MB mpeg 4 file might have 2 hrs of video. Multiply that by 6 to fit onto a 4.37 GB dvd & that's a lot of video.

BTW help with finding mpeg files, see Cant search well help