System and method for media stream synchronization with a base atom index file and an auxiliary atom index file

摘要

An indexing method allows a viewer to control the mode of delivery of program material while minimizing the time offset between audio and video data so that the viewer does not perceive a time delay between the audio and video. Video data frames may be grouped together into units referred to as "Groups of Pictures" (GOP's) comprising one or more frames. Synchronization is performed by correlating audio frames of the audio data with GOP's of the video data. When jumping to various points in an item of program material, this indexing method ensures that a jump is made to the beginning of a GOP. To prevent audio data from being "out of sync", the audio data must be correlated with the corresponding GOP. To do so, an index file for the video data is constructed, and then the video data index file is used to construct an index file for the corresponding audio data. The audio data index file is constructed so that, for the set of audio frames that most closely span the time interval spanned by each GOP, each audio frame in that set is assigned the same atom-relative byte position, which is the beginning of the set of audio frames.