Techniques to perform rate matching for multimedia conference calls

• US 20080043644A1
• Filed: 08/18/2006
• Published: 02/21/2008
• Est. Priority Date: 08/18/2006
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Crinon, Regis J., Chou, Philip A., Moore, Tim, Barkley, Warren V.
• Granted Patent: US 7,898,950 B2
• Time in Patent Office: Days
• US Class Current: 370/261
• CPC Class Codes: H04Q 11/00 Selecting arrangements for multiplex systems multiplex systems H04J
• CPC Class Codes: H04Q 2213/13103 Memory
• CPC Class Codes: H04Q 2213/1324 Conference call
• CPC Class Codes: H04Q 2213/13248 Multimedia
• CPC Class Codes: H04Q 2213/13332 Broadband, CATV, dynamic bandwidth allocation
• CPC Class Codes: H04Q 2213/13335 Simulation, emulation
• CPC Class Codes: H04Q 2213/13337 Picturephone, videotelephony

Abstract

Techniques to perform rate matching for multimedia conference calls are described. An apparatus may comprise a conferencing server and a rate matching module. The rate matching module may be arranged to adjust bit rates between media communications channels for client terminals in a conference call, with the rate matching module to remove video frames from a set of video information received on a first media communications channel to reduce a bit rate for the video information. Other embodiments are described and claimed.

Claims

1. A method, comprising:

receiving a set of video information with a first number of video frames from a first client terminal in a conference call;

receiving a bandwidth estimate for a media communications channel with a second client terminal in said conference call; and

calculating a second number of video frames to remove from said set of video information based on said bandwidth estimate.

2. The method of claim 1, comprising calculating said second number based on a defined structure for said set of video information, said defined structure including multiple video frame types and a frame ordering sequence.

3. The method of claim 1, comprising calculating said second number based on a video frame type and a number of frames for said frame type.

4. The method of claim 1, comprising:

receiving a set of input parameters comprising a description of a frame type composition used in a group of picture structure, a video bit rate for said set of video information, a representative number of bits used for each frame type for said first number of video frames, and a frame ordering sequence; and

sending a set of output parameters comprising a remove frame type, a number of remove frames for said remove frame type, and a location for each remove frame in said set of video information, where said number and location of remove frames are calculated relative to said group of picture structure or relative to a pre-defined time window.

5. The method of claim 1, comprising removing said second number of video frames from said set of video information in accordance with a set of output parameters.

6. The method of claim 1, said bandwidth estimate to represent an instantaneous channel capacity for said media communications channel.

7. The method of claim 1, said bandwidth estimate to represent changes in network conditions for said media communications channel.

8. The method of claim 1, said bandwidth estimate to represent changes in media processing resources for a second client terminal to receive said video information.

9. The method of claim 1, comprising sending said set of video information with a third number of video frames to a second client terminal over said media communications channel, with said third number of video frames to be less than said first number of video frames.

10. An apparatus, comprising:

a conferencing server; and

a rate matching module to adjust bit rates between media communications channels for client terminals in a conference call, said rate matching module to remove video frames from a group of pictures received on a first media communications channel to reduce a bit rate for said group of pictures.

11. The apparatus of claim 10, comprising a crossbar to receive said group of pictures, and identify a second media communications channel to communicate said group of pictures at said reduced bit rate.

12. The apparatus of claim 10, comprising a rate matching calculator to receive a bandwidth estimate for a second media communications channel, and calculate a number of video frames to remove from said group of pictures based on said bandwidth estimate.

13. The apparatus of claim 10, comprising a rate matching calculator to calculate said number based on a defined structure for said group of pictures, said defined structure including multiple video frame types and a frame ordering sequence.

14. The apparatus of claim 10, comprising a rate matching calculator to calculate said number based on a video frame type and a number of video frames for said frame type.

15. The apparatus of claim 10, comprising a rate matching calculator to receive a set of input parameters comprising a description of a frame type composition used in a group of picture structure, a video bit rate for said group of pictures, a number of bits used for each frame type for said first number of video frames, and a frame ordering sequence, said rate matching calculator to send a set of output parameters comprising a remove frame type, a number of remove frames for said remove frame type, and a location for each remove frame in said group of pictures.

16. The apparatus of claim 10, comprising a traffic shaper to remove packets of the underlying transport protocol carrying said number of video frames from said group of pictures in accordance with a set of output parameters.

17. The apparatus of claim 10, comprising a network interface to send said group of pictures over a second media communications channel at said reduced bit rate.

18. A multipoint control unit, comprising:

a first communications interface to receive a video bitstream at a bit rate over a first media communications channel;

a rate matching module coupled to said first communications interface to selectively remove video frames from said video bitstream to reduce said bit rate; and

a second communications interface coupled to said processor, said second communications interface to send said video bitstream at said reduced bit rate over a second media communications channel.

19. The multipoint control unit of claim 18, comprising a video crossbar to receive said video bitstream, and identify said second media communications channel to communicate said video bitstream at said reduced bit rate.

20. The multipoint control unit of claim 18, comprising a rate matching calculator to receive a bandwidth estimate for said second media communications channel, and calculate a number of video frames to remove from said video bitstream to substantially match said bandwidth estimate.

21. The multipoint control unit of claim 18, comprising a rate matching calculator to calculate a number of video frames to selectively remove based on a video frame type and a number of video frames for said frame type.

22. The multipoint control unit of claim 18, comprising a rate matching calculator to receive a set of input parameters comprising a description of a frame type composition used in a group of picture structure, a bit rate for said group of pictures, a number of bits used for each frame type of said video bitstream, and a frame dependency, said rate matching calculator to send a set of output parameters comprising a remove frame type, a number of remove frames for said remove frame type, and a location for each remove frame in said video bitstream, where said numbers and locations of video frames are calculated relative to said group of picture structure or a pre-defined time window.

23. The multipoint control unit of claim 18, comprising a traffic shaper to selectively remove said video frames from said video bitstream in accordance with a set of received output parameters.

24. An article comprising a machine-readable storage medium containing instructions that if executed enable a system to receive a set of video information with a first number of video frames from a first client terminal in a conference call, receive a bit rate for a media communications channel with a second client terminal in said conference call, and calculate a second number of video frames to remove from said set of video information based on said bit rate.

25. The article of claim 24, said machine-readable storage medium comprising a processing device, a computer-readable medium, a communications medium, or a propagated signal.

26. The article of claim 24, further comprising instructions that if executed enable the system to calculate said second number based on a defined structure for said set of video information, said defined structure including multiple video frame types and a frame ordering sequence.

27. The article of claim 24, further comprising instructions that if executed enable the system to receive a set of input parameters comprising a description of a frame type composition used in a group of picture structure, a video bit rate for said set of video information, a number of bits used for each frame type for said first number of video frames, and a frame ordering sequence, and send a set of output parameters comprising a remove frame type, a number of remove frames for said remove frame type, and a location for each remove frame in said set of video information.

28. The article of claim 24, further comprising instructions that if executed enable the system to remove said second number of video frames from said set of video information in accordance with a set of output parameters.