Method and apparatus for synchronizing audio and video data streams in a multimedia system
US5642171A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 8, 1994 |
| Grant date | Jun 24, 1997 |
| Priority date | — |
| Expiry date | Jun 8, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N21/4143
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.