Free Space Atoms

QuickTime Movie File Format Specification, May 1996

Free Space Atoms

Both free and skip atoms designate unused space in the movie data file. These atoms consist only of an atom header (atom size and type fields), followed by the appropriate number of bytes of free space. When reading a QuickTime movie, your application may safely skip these atoms. When writing or updating a movie, you may re-use the space associated with these atom types.