I have made a very short video (.avi) which i need to loop continuously. Are there any programs which can do this smoothly, so you cannot see the transition between 2 videos? I have tried kaffeine, km player and movie player, but none of these seem to work. i am also a linux user, which obviously limits the programs i can use. any ideas are extremely welcome!!

Loop or repeat play is usually a function of the player and not the dvd file.

How long does this very short video file need to repeat?

What I've done for business display type things and also when I project repeating scary scenes on my outdoor wall screen on Halloween is I take my video edited file - open it in my editing program and just drop it over and over again into the timeline. This takes like minutes to replicate the short file for as long as I want - one hour? two hours? Then I re-render it out a one looooong file of a repeated file and burn it to disc.

The you can set your dvd player to repeat and the only time you might see a slight pause is when the looooong dvd file hits the end and then the player starts it over again and there you go!
goodluck