Quicktime File Format (2012-08-14).pdf

Movie AtomsReference MoviesConstantscanMovieImportInPlaceSet this bit if a movie import component must be able to create a movie from a file without having towrite to a separate disk file. Examples include MPEG and AIFF import components.movieImportSubTypeIsFileExtensionSet this bit if the component's subtype is a file extension instead of a Macintosh file type. For example,if you require an import component that opens files with an extension of .doc, set this flag and set yourcomponent subtype to 'DOC '.canMovieImportFilesSet this bit if a movie import component must import files.Quality AtomA quality atom describes the relative quality of a movie. This acts as a tiebreaker if more than one movie meetsthe specified requirements, and it is not otherwise obvious which movie should be played.This would be the case if two qualified movies have the same data rate and CPU speed requirements, forexample, or if one movie requires a higher data rate and another requires a higher CPU speed, but both canbe played on the current system. In these cases, applications should play the movie with the highest quality,as specified in the quality atom.Only one quality atom is allowed in a given reference movie descriptor atom.A quality atom may contain the following fields:SizeThe number of bytes in this quality atom.TypeThe type of this atom; this field must be set to 'rmqu'.QualityThe relative quality of the movie, expressed as a 32-bit integer. A larger number indicates higher quality.A unique value should be given to each movie.2012-08-14 | © 2004, 2012 Apple Inc. All Rights Reserved.127