a movie(.avi) and all movie formats have different properties,
it would be very difficult(but I know makslane could do it.

) to put the files in the right format for game development,
(you can use more than just a .gif you know.

)
the movie files are better use for just movies.
but why exacly would you like to use a .avi or .mpeg?
(I am very confused about this.

)