QuickTime 4 Reference

Compressing Movie Resources When Flattening

An application can create a compressed movie resource when flattening a movie by calling the FlattenMovieData or FlattenMovie function with the flattenCompressMovieResource flag set. This compresses the movie resource stored in the file's data fork, but not the movie resource stored in the resource fork on Mac OS systems. Compressing just the data fork is sufficient for most purposes, including transmission of movies over the Internet, where only the data fork is used.