I also wanted to playback AVIs without them having to be re-scaled, reducing image quality, so the way I did it was...
Say you wanna playback a 640x480 sized anim, create a 1024x512 texture, copy an AVI frame to that texture, then apply that texture, with appropriate texture coordinates (To cut off unused pixels in texture) to a quad in orthographic projection.
It''s probably not the fastest ways of doing it

But it works!
I must say special thanks to NeHe for his AVI tut aswell!
AVI playback/record source...
http://www.davesprogramming.com/section_codebin/doxygen/DGLAVI_8h-source.htmlhttp://www.davesprogramming.com/section_codebin/doxygen/DGLAVI_8cpp-source.html