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

Profile Atom GuidelinesUniversal Featuresis found in the MPEG-4 Elementary Stream Descriptor Atom within the 'esds' sample description atomof the video sample description for the QuickTime video codec of type 'mp4v'.Feature ValuesThe value is a video object type constant that indicates a set of video tools. The list of video object typeconstants is defined in specification ISO/IEC 14496-2, subclause 6.3.3. The least significant 8 bits hold the value.The most significant 24 bits should be set to 0.Example: The Simple Object Type video object is indicated by the value 1.Writer ResponsibilitiesA writer of the MPEG-4 Video Object Type feature should record the 8 bits corresponding to thevideo_object_type_indication found in the VideoObjectLayer within the ES_descriptor’s videoDecoderSpecificConfig. The most significant 24 bits of the value should be set to 0.This feature shouldbe written only for MPEG-4 video of video object type 1 (Video ID). If the MPEG-4 video does not use Video ID(1) for visual_object_type, the esds will have no VideoObjectLayer and consequently novideo_object_type_indication. In this case, no MPEG-4 Video Object Type feature should be written.Note A writer that records the MPEG-4 Video Object Type feature for encoded video using the VideoID visual object type is encouraged to write the MPEG-4 Video Codec and MPEG-4 Video Profilefeatures as well.Feature Value AlgorithmThe MPEG-4 video object type is the least significant 8 bits of the video_object_type_indication foundin the VideoObjectLayer. See ISO/IEC 14496-2, subclause 6.2.3. The VideoObjecLayer is found in theMPEG-4 Elementary Stream Descriptor Atom within the 'esds' sample description atom of the video sampledescription for the QuickTime video codec of type 'mp4v'.Reader ResponsibilitiesA reader of this feature code should compare the recorded value with the set of MPEG-4 video tools supportedby the reader.MPEG-4 Audio CodecContaining profile atomTrack (sound), movie2012-08-14 | © 2004, 2012 Apple Inc. All Rights Reserved.409