Television – Synchronization – Locking of video or audio to reference timebase
Patent
1994-06-08
1997-06-24
Hsia, Sherrie
Television
Synchronization
Locking of video or audio to reference timebase
395806, H04N 504
Patent
active
056421710
ABSTRACT:
A method and apparatus for synchronizing audio and video data streams in a computer system during a multimedia presentation to produce a correctly synchronized presentation. The preferred embodiment of the invention utilizes a nonlinear feedback method for data synchronization. The method of the present invention periodically queries each driver for the current audio and video position (or frame number) and calculates the synchronization error. The synchronization error is used to determine a tempo value adjustment to one of the data stream designed to place the video and audio back in sync. The method then adjusts the audio or video tempo to maintain the audio and video data streams in synchrony. In the preferred embodiment of the invention, the video tempo is changed nonlinearly over time to achieve a match between the video position and the equivalent audio position. The method applies a smoothing function to the determined tempo value to prevent overcompensation. The method of the present invention can operate in any hardware system and in any software environment and can be adapted to existing systems with only minor modifications.
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Baumgartner Donn M.
Dye Thomas A.
Dell USA L.P.
Hsia Sherrie
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