Matinee Rendering Issue

I am trying to create a movie out of a matinee that I have put together, however, when the movie renders and is being played back through windows media player I get a really heavy stutter. Any ideas as to why this is and how to fix it? Any help would be very much appreciated.

If you are trying to play the AVI file recorded at a resolution higher than 720p then it is normal since it is uncompressed. You’ll have to convert it into another format.

Ahh, that seems to have been it, thank you very much.