Mpeg or Avi Encoding-does size matter

[lqdwax]

I have a question that i was unable to find an answer to when i was searching the forums.
It seems that if i take a avi file and put it into a dvd burning program it seems to always take up the same amount of space on the dvd no matter what i reencode at(larger file, smaller file). but if i take an mpeg file and stick on a dvd it seems like whatever the file size is what it will be on the dvd no set size like with the avi. now i am just wondering if i am crazy or this is how it really is. the reason i am asking this is because i am trying to squeeze as much time out of a dvd-5 as i can I have a lot of small movies i would like to fit onto one dvd. THANKS FOR YOUR INPUT

[echooff]

Many apps allow you to dictate file output size, cce, tmpgenc etc. Tmpgenc 3 express is pretty good at doing this and relatively simple to use. I use it for tv episode disk. Tmpgenc 2.5 can also, but requires a little more tweaking from you. CCE, IMHO, is perfect for the job but requires much more knowledge from you to accomplish the job. There are others. Poke around the forum for even more methods. Keep in mind, your file source should dictate the output size. A poor source becomes unviewable below a certain bitrate. A high deff file will allow much more compressability.