| 摘要 |
A system for playing video data ahead of corresponding audio data in order to help maintain synchronization between the audio data and the video data. Two software objects or filters are used to process the video data. An initial start time of the video data is determined and, if possible, the frame of video data is decoded or else it is selectively dropped in order to help maintain synchronization. An adaptive offset time is applied to the initial start time of a decoded frame of video data in order to produce an adjusted start time for the decoded frame. The offset time can be adapted to include a refresh offset related to sweep delays in computer monitors, a target offset which helps to build in a play-ahead margin for future late frames, and an earliness offset which is diminishing over time to help smooth transitions due to changing apparent video processing power. Additionally, the playing of video data can be slowed down in response to a low condition of the audio buffer. This avoids sound breaks and also helps to maintain synchronization.
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