System and method for a conference server architecture for low delay and distributed conferencing applications

Abstract

Systems and methods for conducting a multi-endpoint video signal conference are provided. Conferencing endpoints are linked by pairs of a reliable and a less reliable communication channel. Conference video signals are scaleable coded in base layer and enhancement layers format. Video signal base layers, which correspond to a minimum picture quality, are communicated over reliable channels. The video signal enhancements layers may be communicated over the less reliable channels. A conference server mediates the switching of video layer information from transmitting endpoints to receiving endpoints without any intermediate coding or re-coding operations. The video conference can be integrated with an audio conference using either scalable coded audio signals or non-scaleable coded audio signals.

What is claimed is: 
     
         1 . A method for conferencing between a scalable video coding server and at least one receiving endpoint linked to the server by a communication channel, comprising:
 receiving, at the server, a plurality of media signals having different signal characteristics but representing a same content, each media signal comprising a plurality of packets;   selectively forwarding, by the server, at least one, but not all, of the media signals representing the same content to the at least one receiving endpoint over the communication channel; and   improving, by the server, a quality of service of the communication channel over the quality of service the communication channel would have but for the use of the server.   
     
     
         2 . The method of  claim 1 , wherein the signal characteristics comprise at least one of a spatial resolution, a bit rate, a picture quality, or a frame rate. 
     
     
         3 . The method of  claim 1 , wherein the improving of the quality of service of the communication channel comprises repeating, by the server, at least one packet of the plurality of packets included in the one of the plurality of media signals. 
     
     
         4 . The method of  claim 3 , wherein the one of the plurality of media signals is the media signal with at least one of the lowest spatial resolution, the lowest bit rate, the lowest picture quality, or the lowest frame rate of all of the plurality of media signals. 
     
     
         5 . The method of  claim 1 , wherein the improving of the quality of service of the communication channel comprises transmitting, by the server, protected by a Forward Error Correction, at least one packet of the plurality of packets included in the one of the plurality of media signals. 
     
     
         6 . The method of  claim 5 , wherein the one of the plurality of media signals is the media signal with at least one of the lowest spatial resolution, the lowest bit rate, the lowest picture quality, or the lowest frame rate of all of the plurality of media signals. 
     
     
         7 . The method of  claim 1 , wherein the improving of the quality of service of the communication channel comprises caching, by the server, at least one packet of the plurality of packets included in the one of the plurality of media signals, and retransmit the at least one cached packet upon request by the receiving endpoint. 
     
     
         8 . The method of  claim 7 , wherein the one of the plurality of media signals is the media signal with at least one of the lowest spatial resolution, the lowest bit rate, the lowest picture quality, or the lowest frame rate of all of the plurality of media signals. 
     
     
         9 . The method of  claim 1 , wherein a sending endpoint is connected to the server over a second communication channel, further comprising improving, by the sending endpoint, a quality of service of the second communication channel over the quality of service the second communication channel would have but for the use of the sending endpoint. 
     
     
         10 . The method of  claim 9 , wherein the improving of the quality of service of the second communication channel comprises repeating, by the sending endpoint, at least one packet of the plurality of packets included in the one of the plurality of media signals, and discarding, by the server, the repeated packet in case the at least one packet has been received. 
     
     
         11 . The method of  claim 9 , wherein the improving of the quality of service of the second communication channel comprises transmitting, by the sending endpoint, protected by a Forward Error Correction, at least one packet of the plurality of packets included in the one of the plurality of media signals, and reconstructing, by the server, the at least one packet in case it was not received by the server, using the Forward Error Correction. 
     
     
         12 . The method of  claim 9 , wherein the improving of the quality of service of the second communication channel comprises caching, by the sending endpoint, at least one packet of the plurality of packets included in the one of the plurality of media signals, retransmitting, by the second endpoint, the at least one cached packet upon request by the server, and requesting, by the server, retransmission of the at least one cached packet in case the at least one packet has not been received. 
     
     
         13 . A non-transitory computer readable medium comprising a set of executable instructions to direct a processor to:
 receive, at a scalable video coding server, a plurality of media signals having different signal characteristics but representing a same content, each media signal comprising a plurality of packets;   selectively forward, by the server, at least one, but not all, of the media signals representing the same content to the at least one receiving endpoint over the communication channel; and   improve, by the server, a quality of service of the communication channel over the quality of service the communication channel would have but for the use of the server.   
     
     
         14 . The non-transitory computer readable medium of  claim 13 , wherein the signal characteristics comprise at least one of a spatial resolution, a bit rate, a picture quality, or a frame rate. 
     
     
         15 . The non-transitory computer readable medium of  claim 13 , wherein the improve of the quality of service of the communication channel comprises repeat, by the server, at least one packet of the plurality of packets included in the one of the plurality of media signals. 
     
     
         16 . The non-transitory computer readable medium of  claim 15 , wherein the one of the plurality of media signals is the media signal with at least one of the lowest spatial resolution, the lowest bit rate, the lowest picture quality, the lowest frame rate of all of the plurality of media signals. 
     
     
         17 . The non-transitory computer readable medium of  claim 13 , wherein the improve of the quality of service of the communication channel comprises transmit, by the server, protected by a Forward Error Correction, at least one packet of the plurality of packets included in the one of the plurality of media signals. 
     
     
         18 . The non-transitory computer readable medium of  claim 17 , wherein the one of the plurality of media signals is the media signal with at least one of the lowest spatial resolution, the lowest bit rate, the lowest picture quality, or the lowest frame rate of all of the plurality of media signals. 
     
     
         19 . The non-transitory computer readable medium of  claim 13 , wherein the improve of the quality of service of the communication channel comprises cache, by the server, at least one packet of the plurality of packets included in the one of the plurality of media signals, and retransmit the at least one cached packet upon request by the receiving endpoint. 
     
     
         20 . The non-transitory computer readable medium of  claim 19 , wherein the one of the plurality of media signals is the media signal with at least one of the lowest spatial resolution, the lowest bit rate, the lowest picture quality, or the lowest frame rate of all of the plurality of media signals. 
     
     
         21 . The non-transitory computer readable medium of  claim 13 , wherein a sending endpoint is connected to the server over a second communication channel, further comprising executable instructions to direct the processor to improve, by the sending endpoint, a quality of service of the second communication channel over the quality of service the second communication channel would have but for the use of the sending endpoint. 
     
     
         22 . The non-transitory computer readable medium of  claim 21 , wherein improve the quality of service of the second communication channel comprises repeat, by the sending endpoint, at least one packet of the plurality of packets included in the one of the plurality of media signals, and discard, by the server, the repeated packet in case the at least one packet has been received. 
     
     
         23 . The non-transitory computer readable medium of  claim 21 , wherein improve the quality of service of the second communication channel comprises transmit, by the sending endpoint, protected by a Forward Error Correction, at least one packet of the plurality of packets included in the one of the plurality of media signals, and reconstruct, by the server, the at least one packet in case it was not received by the server, using the Forward Error Correction. 
     
     
         24 . The non-transitory computer readable medium of  claim 21 , wherein improve the quality of service of the second communication channel comprises cache, by the sending endpoint, at least one packet of the plurality of packets included in the one of the plurality of media signals, retransmit, by the second endpoint, the at least one cached packet upon request by the server, and request, by the server, retransmission of the at least one cached packet in case the at least one packet has not been received. 
     
     
         25 . An apparatus for conferencing, comprising:
 a scalable video coding server linked to at least one receiving endpoint by a communication channel,   wherein the server receives a plurality of media signals having different signal characteristics but representing a same content, each media signal comprising a plurality of packets,   wherein the server selectively forwards at least one, but not all, of the media signals representing the same content to the at least one receiving endpoint over the communication channel; and   wherein the server improves a quality of service of the communication channel over the quality of service the communication channel would have but for the use of the server.   
     
     
         26 . The apparatus of  claim 25 , wherein the signal characteristics comprise at least one of a spatial resolution, a bit rate, a picture quality, or a frame rate. 
     
     
         27 . The apparatus of  claim 25 , wherein the improving of the quality of service of the communication channel comprises the server repeating at least one packet of the plurality of packets included in the one of the plurality of media signals. 
     
     
         28 . The apparatus of  claim 27 , wherein the one of the plurality of media signals is the media signal with at least one of the lowest spatial resolution, the lowest bit rate, the lowest picture quality, or the lowest frame rate of all of the plurality of media signals. 
     
     
         29 . The apparatus of  claim 25 , wherein the improving of the quality of service of the communication channel comprises the server transmitting, protected by a Forward Error Correction, at least one packet of the plurality of packets included in the one of the plurality of media signals. 
     
     
         30 . The apparatus of  claim 29 , wherein the one of the plurality of media signals is the media signal with at least one of the lowest spatial resolution, the lowest bit rate, the lowest picture quality, or the lowest frame rate of all of the plurality of media signals. 
     
     
         31 . The conferencing system of  claim 25 , wherein the improving of the quality of service of the communication channel comprises the server caching at least one packet of the plurality of packets included in the one of the plurality of media signals, and retransmit the at least one cached packet upon request by the receiving endpoint. 
     
     
         32 . The apparatus of  claim 31 , wherein the one of the plurality of media signals is the media signal with at least one of the lowest spatial resolution, the lowest bit rate, the lowest picture quality, or the lowest frame rate of all of the plurality of media signals. 
     
     
         33 . The apparatus of  claim 25 , wherein the server is connected to a sending endpoint over a second communication channel, wherein the sending improves a quality of service of the second communication channel over the quality of service the second communication channel would have but for the use of the sending endpoint. 
     
     
         34 . The apparatus of  claim 33 , wherein the improving of the quality of service of the second communication channel comprises the sending endpoint repeating at least one packet of the plurality of packets included in the one of the plurality of media signals, and the server discarding the repeated packet in case the at least one packet has been received. 
     
     
         35 . The apparatus of  claim 33 , wherein the improving of the quality of service of the second communication channel comprises the sending endpoint transmitting, protected by a Forward Error Correction, at least one packet of the plurality of packets included in the one of the plurality of media signals, and the server reconstructing the at least one packet in case it was not received by the server, using the Forward Error Correction. 
     
     
         36 . The apparatus of  claim 33 , wherein the improving of the quality of service of the second communication channel comprises the sending endpoint caching at least one packet of the plurality of packets included in the one of the plurality of media signals, and retransmitting the at least one cached packet upon request by the server, and the server requesting retransmission of the at least one cached packet in case the at least one packet has not been received.