Methods and systems for synchronizing data streams

• US 6,957,266 B2
• Filed: 02/22/2005
• Issued: 10/18/2005
• Est. Priority Date: 01/15/2002
• Status: Expired due to Fees

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Evans, Glenn F.
• Primary Examiner(s): Nguyen, John B
• Application Number:
  US11/062,692
• Publication Number:
  US 20050151676A1
• Time in Patent Office: 238 Days
• Field of Search: 341/50, 348/500, 348/512, 348/513, 348/423.1, 713/400, 713/500, 713/600, 709/220, 709/201, 709/231, 709/236
• US Class Current: 709/231
• CPC Class Codes: H04N 21/2368 Multiplexing of audio and video streams
• CPC Class Codes: H04N 21/4143 embedded in a Personal Computer [PC]
• CPC Class Codes: H04N 21/4305 Synchronising client clock from received content stream, e.g. locking decoder clock with encoder clock, extraction of the PCR packets arrangements for synchronising receiver with transmitter by comparing receiver clock with transmitter clock H04L7/0012; arrangements for synchronising receiver with transmitter wherein the receiver takes measures against momentary loss of synchronisation H04L7/0083
• CPC Class Codes: H04N 21/43072 of multiple content streams on the same device
• CPC Class Codes: H04N 21/4341 Demultiplexing of audio and video streams
• CPC Class Codes: H04N 21/4344 Remultiplexing of multiplex streams, e.g. by modifying time stamps or remapping the packet identifiers

Abstract

Methods and systems are provided for synchronizing various time-stamped data streams. The data streams can be synchronized to another data stream or to a point of reference such as a reference clock. In one embodiment, synchronization processing takes place in association with a filter graph comprising multiple filters. The filter graph is configured to process multiple timestamped data streams for rendering the data streams in accordance with data stream timestamps. A synchronization module is provided and is associated with the filter graph queries individual filters of the filter graph to ascertain input timestamp-to-output timestamp mappings. The module computes adjustments that are to be made to output timestamps in order to synchronize the data streams, and then instructs queried filters to adjust their output timestamps in accordance with its adjustment computations.

Claims

1. One or more computer-readable media having computer-readable instructions thereon which, when executed by one or more processors, cause the one or more processors to:

define a skip value tolerance that can be used to ascertain when synchronization processing of multiple data streams should take place;

ascertain whether any input timestamp-to-output timestamp mappings associated with any of the multiple data streams meet or exceed the skip value tolerance; and

synchronize the multiple data streams if any input timestamp-to-output timestamp mappings meet or exceed the skip value tolerance.

2. The computer-readable media of claim 1, wherein the instructions cause the one or more processors to synchronize to a common data stream.

3. The computer-readable media of claim 1, wherein the instructions cause the one or more processors to synchronize to a reference clock.

4. The computer-readable media of claim 1, wherein one of the multiple data streams comprises a video stream.

5. The computer-readable media of claim 1, wherein one of the multiple data streams comprises an audio stream.

6. The computer-readable media of claim 1, wherein one of the multiple data streams comprises a video stream and another of the multiple data streams comprises a video stream.