Video Freezes but audio play in Media Player

Archived from groups: microsoft.public.windowsxp.video (More info?)

I have some downloaded AVI files which the video freezes
up while the audio continues. I move the slide bar over
and the video updates for a couple of frames and then
freezes again. This also happens in other video players
like ATI. I know that these files work because I got
them from another source that plays them with no issues.
What could be causing the problem that both players do
not play these files correctly?