SYSTEM AND METHOD FOR MULTIPOINT CONFERENCING WITH SCALABLE VIDEO CODING SERVERS AND MULTICAST

• US 20080239062A1
• Filed: 10/01/2007
• Published: 10/02/2008
• Est. Priority Date: 09/29/2006
• Status: Active Grant

• Current Assignee: Vidyo Incorporated (Enghouse Systems Limited)
• Original Assignee: Vidyo Incorporated (Enghouse Systems Limited)
• Inventors: Eleftheriadis, Alexandros, Shapiro, Ofer, Civanlar, Reha Mehaet
• Granted Patent: US 8,502,858 B2
• Time in Patent Office: Days
• US Class Current: 348/14.09
• CPC Class Codes: H04L 65/403 Arrangements for multi-party communication, e.g. for conferences data switching systems for conference H04L12/18; arrangements for connecting several subscribers to a common circuit, i.e. affording conference facilities H04M3/56; television conferencing systems H04N7/15
• CPC Class Codes: H04L 65/611 for multicast or broadcast systems for broadcast or conference H04L12/18; arrangements for broadcast or distribution combined with broadcast H04H20/00; arrangements for broadcast applications with a direct linkage to broadcast information or to broadcast space-time H04H60/00; selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS], H04W4/06
• CPC Class Codes: H04L 65/80 Responding to QoS
• CPC Class Codes: H04L 67/5683 Storage of data provided by user terminals, i.e. reverse caching
• CPC Class Codes: H04N 19/30 using hierarchical techniques, e.g. scalability H04N19/63 takes precedence
• CPC Class Codes: H04N 21/2662 Controlling the complexity of the video stream, e.g. by scaling the resolution or bitrate of the video stream based on the client capabilities
• CPC Class Codes: H04N 21/6405 Multicasting data broadcast and multicast in packet switching networks H04L12/18
• CPC Class Codes: H04N 21/6408 Unicasting
• CPC Class Codes: H04N 7/152 Multipoint control units therefor

Abstract

A multicast scalable video communication server (MSVCS) is disposed in a multi-endpoint video conferencing system having multicast capabilities and in which audiovisual signals are scalably coded. The MVCVS additionally has unicast links to endpoints. The MSVCS caches audiovisual signal data received from endpoints over multicast communication channels, and retransmits the data over either unicast or multicast communication channels to an endpoint that requests the cached data.

Claims

1. A multi-endpoint video conferencing system, wherein audiovisual signals are scalably coded into layers including a base layer and one or more enhancement layers, the conferencing system comprising:

a plurality of endpoints that individually can receive and/or transmit scalable audiovisual signals;

a multicast scalable video communication server (MSVCS) linked to each of the endpoints by a corresponding unicast communication channel;

a communication network that provides a plurality of multicast communication channels linking the endpoints and the MSVCS,

wherein the endpoints are configured to transmit their individual audiovisual signal layers to other endpoints and the MSVCS using the plurality of multicast communication channels, and wherein the MSVCS is configured to cache audiovisual signal data received over the plurality of multicast communication channels from the plurality of the endpoints, and retransmit them data over a unicast communication channel to an endpoint that requests the cached audiovisual signal data over its unicast communication channel.

2. The system of claim 1, wherein endpoints perform rate matching and resolution selection for personalized layout for received audiovisual signal data from another endpoint by joining specific multicast communication channel groups that are used for transmission by the other endpoint.

3. The system of claim 1, wherein the MSVCS is further configured to perform the functions of a multicast router.

4. The system of claim 1, further comprising at least one endpoint which is linked to the MSVCS only over a unicast communication channel and which does not have access to any multicast communication channel, wherein the MSVCS is further configured to operate as an SVCS or Compositing SVCS for transmitting data from multicast-enabled endpoints to the at least one endpoint that is linked only over a unicast communication channel and, conversely, transmit audiovisual data received from that endpoint to the multicast-enabled endpoints using corresponding multicast communication channels.

5. The system of claim 1, wherein the MSVCS is further configured to identify if any multicast communication channels are available to and between the endpoints by first assigning one multicast communication channel group address to each of the endpoints and transmitting all the assignments to each endpoint over its corresponding unicast communication channel, so that the endpoints can join all the assigned multicast communication channel group addresses and each endpoint can transmit a test packet to the multicast communication channel group address assigned to it, and report after a period of time to the MSVCS the list of other endpoints or multicast communication channel group addresses from which they have received test packets.

6. A multi-endpoint video conferencing system, wherein audiovisual signals are scalably coded into layers including a base layer and one or more enhancement layers, the conferencing system comprising:

a plurality of endpoints that individually can receive and transmit scalable audiovisual signals;

a multicast scalable video communication server (MSVCS) linked to each of the endpoints by one or more corresponding unicast communication channels;

a communication network that provides a plurality of multicast communication channels linking the MSVCS to the endpoints,

wherein the endpoints are configured to transmit their individual audiovisual signal layer data to the MSVCS using their corresponding unicast communication channels, and wherein the MSVCS is configured to retransmit received audiovisual signal layer data to the endpoints over the plurality of multicast communication channels.

7. The system of claim 6, wherein endpoints perform rate matching and resolution selection for personalized layout for received data from the other endpoints by joining specific multicast communication channel groups that are used for transmission by the MSVCS.

8. The system of claim 6, wherein the MSVCS is further configured to cache audiovisual signal data received from the plurality of the endpoints, and retransmit the data over a unicast communication channel to an endpoint that requests the cached audiovisual signal data over its corresponding unicast communication channel.

9. The system of claim 6, wherein the MSVCS is configured, prior to creating the output video signal that is forwarded to a receiving endpoint, to selectively eliminate or modify portions of input video signals received from transmitting endpoints that correspond to layers higher than the base spatial or quality layer, and explicitly code or signal use of lower spatial or quality layer data in the output video signal.

10. The system of claim 6, wherein the MSVCS is further configured to perform the functions of a multicast router.

11. The system of claim 6, further comprising at least one endpoint which is linked to the MSVCS only over a unicast communication channel and which does not have access to any multicast communication channel, wherein the MSVCS is further configured to operate as an SVCS or Compositing SVCS for transmitting data from the multicast-enabled endpoints to the at least one endpoint that is linked only over a unicast communication channel and, conversely, transmit audiovisual data received from that endpoint to the multicast-enabled endpoints using corresponding multicast communication channels.

12. The system of claim 6, wherein the MSVCS is further configured to identify if any multicast communication channels are available to the endpoints by selecting a multicast communication channel group address and transmitting it to all the endpoints over their corresponding unicast communication channels, so that the endpoints can join the selected multicast communication channel group address, and report after a period of time to the MSVCS if they have received a test packet transmitted by the MSVCS to the selected multicast communication channel group address.

13. A method for operating a multi-endpoint video conferencing system, wherein audiovisual signals are scalably coded into layers including a base layer and one or more enhancement layers, the conferencing system comprising:

a plurality of endpoints that individually can receive and/or transmit scalable audiovisual signals;

a multicast scalable video communication server (MSVCS) linked to each of the endpoints by a corresponding unicast communication channel;

a communication network that provides a plurality of multicast communication channels linking the endpoints and the MSVCS,

the method comprising;

transmitting by the endpoints their individual audiovisual signal layers to other endpoints and the MSVCS using the plurality of multicast communication channels;

at the MSVCS, caching audiovisual signal data received over the plurality of multicast communication channels from the plurality of the endpoints;

and retransmitting cached data over a unicast communication channel to an endpoint that requests the cached audiovisual signal data over its unicast communication channel.

14. The method of claim 13, further comprising,

at an endpoint, performing rate matching and resolution selection for personalized layout for received audiovisual signal data from another endpoint by joining specific multicast communication channel groups that are used for transmission by the another endpoint.

15. The method of claim 13, further comprising using the MSVCS to perform the functions of a multicast router.

16. The method of claim 13, wherein at least one endpoint which is linked to the MSVCS only over a unicast communication channel and which does not have access to any multicast communication channel, the method further comprising:

operating the MSVCS as an SVCS or Compositing SVCS for transmitting data from multicast-enabled endpoints to the at least one endpoint that is linked only over a unicast communication channel; and

conversely, transmitting audiovisual data received from that endpoint to the multicast-enabled endpoints using corresponding multicast communication channels.

17. The method of claim 13, further comprising:

using the MSVCS to identify if any multicast communication channels are available to and between the endpoints by first assigning one multicast communication channel group address to each of the endpoints and transmitting all the assignments to each endpoint over its corresponding unicast communication channel, so that the endpoints can join all the assigned multicast communication channel group addresses and each endpoint can transmit a test packet to the multicast communication channel group address assigned to it, and report after a period of time to the MSVCS the list of other endpoints or multicast communication channel group addresses from which they have received test packets.

25. Computer readable media comprising a set of instructions to perform the steps recited in at least one of the method claims 13-24.

18. A method for operating a multi-endpoint video conferencing system, wherein audiovisual signals are scalably coded into layers including a base layer and one or more enhancement layers, the conferencing system comprising:

a plurality of endpoints that individually can receive and transmit scalable audiovisual signals;

a multicast scalable video communication server (MSVCS) linked to each of the endpoints by one or more corresponding unicast communication channels;

a communication network that provides a plurality of multicast communication channels linking the MSVCS to the endpoints,

the method comprising;

at the endpoints, transmitting their individual audiovisual signal layer data to the MSVCS using their corresponding unicast communication channels; and

at the MSVCS retransmitting received audiovisual signal layer data to the endpoints over the plurality of multicast communication channels.

19. The method of claim 18, wherein endpoints perform rate matching and resolution selection for personalized layout for received data from the other endpoints by joining specific multicast communication channel groups that are used for transmission by the MSVCS.

20. The method of claim 18, further comprising:

at the MSVCS,

caching audiovisual signal data received from the plurality of the endpoints; and

retransmitting the data over a unicast communication channel to an endpoint that requests the cached audiovisual signal data over its corresponding unicast communication channel.

21. The method of claim 18, further comprising:

prior to creating the output video signal that is forwarded to a receiving endpoint, using the MSVCS to selectively eliminate or modify portions of input video signals received from transmitting endpoints that correspond to layers higher than the base spatial or quality layer; and

explicitly coding or signaling use of lower spatial or quality layer data in the output video signal.

22. The method of claim 18, further comprising using the MSVCS to perform the functions of a multicast router.

23. The method of claim 18, wherein at least one endpoint is linked to the MSVCS only over a unicast communication channel and does not have access to any multicast communication channel, the method further comprising operating the MSVCS as an SVCS or Compositing SVCS for transmitting data from multicast-enabled endpoints to the at least one endpoint that is linked only over a unicast communication channel and, conversely, transmitting audiovisual data received from that endpoint to the multicast-enabled endpoints using corresponding multicast communication channels.

24. The method of claim 18, further comprising using the MSVCS to identify if any multicast communication channels are available to the endpoints by selecting a multicast communication channel group address and transmitting it to all the endpoints over their corresponding unicast communication channels, so that the endpoints can join the selected multicast communication channel group address, and report after a period of time to the MSVCS if they have received a test packet transmitted by the MSVCS to the selected multicast communication channel group address.