RESOURCE-ADAPTIVE VIDEO ENCODER SHARING IN MULTIPOINT CONTROL UNIT

• US 20140375756A1
• Filed: 06/13/2014
• Published: 12/25/2014
• Est. Priority Date: 06/24/2013
• Status: Active Grant

• Current Assignee: Dialogic, Inc. (Enghouse Systems Limited)
• Original Assignee: Dialogic, Inc. (Enghouse Systems Limited)
• Inventors: Yang, Kyeong Ho, Tun, Myo, Kolakowski, Lawrence
• Granted Patent: US 9,210,381 B2
• Time in Patent Office: Days
• US Class Current: 348/14.09
• CPC Class Codes: H04N 19/42 characterised by implementation details or hardware specially adapted for video compression or decompression, e.g. dedicated software implementation H04N19/635 takes precedence
• CPC Class Codes: H04N 19/503 involving temporal prediction adaptive coding with adaptive selection between spatial and temporal predictive coding H04N19/107; adaptive coding with adaptive selection among a plurality of temporal predictive coding modes H04N19/109
• CPC Class Codes: H04N 19/593 involving spatial prediction techniques
• CPC Class Codes: H04N 19/91 Entropy coding, e.g. variable length coding [VLC] or arithmetic coding
• CPC Class Codes: H04N 7/152 Multipoint control units therefor

Abstract

Systems and methods of video conferencing, in which existing video encoders associated with a multipoint control unit (MCU) can be shared among conference participant devices, depending upon the availability of processor and/or memory resources for the MCU. In making decisions regarding the sharing of video encoders, the systems and methods take into account various parameters associated with potential conference participant devices and the total cost of the processor/memory resources for the MCU, to determine whether a video encoder of the MCU can be shared with, or allocated to, the respective conference participant devices. By determining whether to share or allocate a video encoder of the MCU, depending upon the available processor/memory resources for the MCU, the MCU can be made to operate with increased stability. The systems and methods can be applied to any application that sends the same content to multiple receivers, including announcement and video streaming applications.

Claims

1. In a multimedia communications system, a method of allocating one or more of processor resources and memory resources of a multimedia communications server, the multimedia communications server including at least one video encoder, the multimedia communications system including a plurality of multimedia participant devices communicably coupleable to the multimedia communications server over at least one network, the method comprising:

receiving, at the multimedia communications server, a request from a respective multimedia participant device to join a multimedia session, the request including one or more video encoder attributes;

determining, by the multimedia communications server using at least some of the one or more video encoder attributes, a first cost of sharing operations of a video encoder among the respective multimedia participant device and at least one other multimedia participant device participating in the multimedia session;

determining, by the multimedia communications server, a second cost of allocating one or more of the processor resources and the memory resources for implementing an additional video encoder for use with the respective multimedia participant device;

comparing the first cost with the second cost to obtain a comparison result; and

based at least upon the comparison result, performing, by the multimedia communications server, one of sharing the operations of the video encoder with the respective multimedia participant device, and allocating the one or more of the processor resources and the memory resources for implementing the additional video encoder for use with the respective multimedia participant device.

2. The method of claim 1 wherein the one or more video encoder attributes include at least a frame size and a target bitrate, and wherein the determining of the first cost of sharing the operations of the video encoder includes determining one or more of a third cost associated with a difference in frame sizes supported by the video encoder and the respective multimedia participant device, and a fourth cost associated with a target bitrate range of the video encoder.

3. The method of claim 2 wherein the determining of the first cost of sharing the operations of the video encoder further includes obtaining a sum of the third cost associated with the difference in the frame sizes and the fourth cost associated with the target bitrate range.

4. The method of claim 3 wherein the request further includes one or more video parameters, the one or more video parameters including at least a layout identifier and a codec type, and wherein the determining of the first cost of sharing the operations of the video encoder further includes assigning a predetermined maximum cost to the first cost if one of the layout identifier and the codec type is not supported by the video encoder.

5. The method of claim 4 wherein the determining of the first cost of sharing the operations of the video encoder further includes assigning the predetermined maximum cost to the first cost if the target bitrate is outside the target bitrate range of the video encoder.

6. The method of claim 2 wherein the determining of the first cost of sharing the operations of the video encoder further includes determining whether the video encoder is a scalable video encoder.

7. The method of claim 6 wherein the target bitrate range of the scalable video encoder is defined by a minimum bitrate and a maximum bitrate, and wherein the determining of the first cost of sharing the operations of the video encoder further includes setting the maximum bitrate to be equal to the target bitrate if the minimum bitrate multiplied by a predetermined bitrate range factor is higher than or equal to the target bitrate.

8. The method of claim 7 wherein the determining of the first cost of sharing the operations of the video encoder further includes setting the minimum bitrate to be equal to the target bitrate if the target bitrate multiplied by the predetermined bitrate range factor is higher than or equal to the maximum bitrate.

9. The method of claim 1 wherein the determining of the second cost of allocating the one or more of the processor resources and the memory resources for implementing the additional video encoder includes determining a current availability of processor resources for the multimedia communications server.

10. The method of claim 9 wherein the determining of the current availability of processor resources for the multimedia communications server includes determining a reference video encoder load for the multimedia communications server.

11. The method of claim 10 wherein the reference video encoder load corresponds to a central processing unit (CPU) load for running a reference video encoder having one or more of a predetermined resolution, a predetermined bitrate, and a predetermined frame rate, and wherein the method further comprises:

obtaining one or more scaling factors for one or more of the predetermined resolution, the predetermined bitrate, and the predetermined frame rate, respectively, of the reference video encoder if the additional video encoder does not support one or more of the predetermined resolution, the predetermined bitrate, and the predetermined frame rate.

12. The method of claim 9 wherein the determining of the second cost of allocating the one or more of the processor resources and the memory resources for implementing the additional video encoder further includes determining a current availability of memory resources for the multimedia communications server.

13. The method of claim 12 wherein the determining of the second cost of allocating the one or more of the processor resources and the memory resources for implementing the additional video encoder further includes assigning a predetermined maximum cost to the second cost if sufficient memory resources are not available to the multimedia communications server.

14. A multimedia communications server for use in a multimedia communications system, the multimedia communications system including a plurality of multimedia participant devices communicably coupleable to the multimedia communications server over at least one network, the multimedia communications server comprising:

at least one video encoder; and

a controller including at least one processor operative to execute at least one program out of at least one memory;

to receive a request from a respective multimedia participant device to join a multimedia session, the request including one or more video encoder attributes;

to determine, using at least some of the one or more video encoder attributes, a first cost of sharing operations of the at least one video encoder among the respective multimedia participant device and at least one other multimedia participant device participating in the multimedia session;

to determine a second cost of allocating one or more of processor resources and memory resources for implementing an additional video encoder for use with the respective multimedia participant device;

to compare the first cost with the second cost to obtain a comparison result; and

based at least upon the comparison result, to perform one of sharing the operations of the video encoder with the respective multimedia participant device, and allocating one or more of the processor resources and the memory resources for implementing the additional video encoder for use with the respective multimedia participant device.

15. The multimedia communications server of claim 14 wherein the one or more video encoder attributes include at least a frame size and a target bitrate, and wherein the at least one processor is further operative to execute the at least one program out of the at least one memory:

to determine one or more of a third cost associated with a difference in frame sizes supported by the video encoder and the respective multimedia participant device, and a fourth cost associated with a target bitrate range of the video encoder.

16. The multimedia communications server of claim 15 wherein the at least one processor is further operative to execute the at least one program out of the at least one memory:

to determine the first cost of sharing the operations of the at least one video encoder as a sum of the third cost associated with the difference in the frame sizes and the fourth cost associated with the target bitrate range.

17. In a multimedia communications system, a method of handling packet errors associated with multimedia content received at a respective one of a plurality of multimedia participant devices from a multimedia communications server, the multimedia communications server including at least one video encoder, the plurality of multimedia participant devices being communicably coupleable to the multimedia communications server over at least one network, the method comprising:

receiving, at the multimedia communications server, at least one report packet from a respective multimedia participant device, the at least one report packet containing packet error feedback information, the plurality of multimedia participant devices including the respective multimedia participant device participating in a multimedia session and sharing operations of the same video encoder;

determining, at the multimedia communications server, whether the packet error feedback information includes one or more of a request for an intra-coded frame and an estimated available bandwidth of the respective multimedia participant device;

in the event the packet error feedback information includes the request for the intra-coded frame, determining a first cost of sending the intra-coded frame to the plurality of multimedia participant devices participating in the multimedia session and sharing the operations of the same video encoder;

in the event the packet error feedback information includes the estimated available bandwidth of the respective multimedia participant device, determining a second cost of adjusting an average bitrate employed in the multimedia session; and

based at least upon one or more of the first cost and the second cost, performing, by the multimedia communications server, one or more of sending the intra-coded frame to the plurality of multimedia participant devices, and adjusting the average bitrate employed in the multimedia session.

18. The method of claim 17 wherein the determining of the first cost of sending the intra-coded frame includes obtaining a cost function of a plurality of cost factors, the plurality of cost factors including a number of additional bits required to encode a current frame using intra-coding as opposed to using inter-coding, and a total number of the plurality of multimedia participant devices sharing the operations of the same video encoder.

19. The method of claim 18 wherein the determining of the first cost of sending the intra-coded frame includes weighting the first cost by a number of inter-coded frames scheduled to be sent to a receiving side of the multimedia session before sending a next scheduled intra-coded frame.

20. The method of claim 19 further comprising:

based at least upon the first cost, performing, by the multimedia communications server, one of (1) sending the intra-coded frame substantially immediately, (2) ignoring the request for the intra-coded frame, and (3) implementing an additional video encoder or designating another existing video encoder for use by the respective multimedia participant device.

21. The method of claim 20 wherein the at least one video encoder employs a predetermined quantization parameter for encoding the multimedia content, and wherein the selecting between (1) the sending of the intra-coded frame substantially immediately, and (2) the implementing of the additional video encoder or the designating of another existing video encoder for use by the respective multimedia participant device, is based at least upon an average value of the quantization parameter.

22. The method of claim 17 wherein the determining of the second cost of adjusting the average bitrate employed in the multimedia session includes obtaining one or more of (1) a current bitrate for the at least one video encoder, (2) the estimated available bitrate for the respective multimedia participant device, (3) a maximum available bitrate among available bitrates for the plurality of multimedia participant devices, and (4) a minimum available bitrate among the available bitrates for the plurality of multimedia participant devices.

23. The method of claim 22 further comprising:

setting, by the multimedia communications server, the current bitrate for the at least one video encoder to be equal to the estimated available bitrate for the respective multimedia participant device if (1) the estimated available bitrate calls for an increase in the current bitrate, and (2) the estimated available bitrate is lower than the minimum available bitrate.

24. The method of claim 22 further comprising:

setting, by the multimedia communications server, the current bitrate for the at least one video encoder to be equal to the minimum available bitrate among the available bitrates for the plurality of multimedia participant devices if (1) the estimated available bitrate calls for an increase in the current bitrate, and (2) the estimated available bitrate is lower than the maximum available bitrate multiplied by a first predetermined factor.

25. The method of claim 24 further comprising:

setting, by the multimedia communications server, the current bitrate for the at least one video encoder to be equal to the minimum available bitrate among the available bitrates for the plurality of multimedia participant devices if (1) the estimated available bitrate calls for an increase in the current bitrate, (2) the estimated available bitrate is higher than or equal to the maximum available bitrate multiplied by the first predetermined factor, and (3) an acceptable quality of experience for multimedia transmissions can be achieved with the current bitrate set to be equal to the minimum available bitrate.

26. The method of claim 25 further comprising:

implementing, by the multimedia communications server, an additional video encoder, or designating, by the multimedia communications server, another existing video encoder for use by the respective multimedia participant device if (1) the estimated available bitrate calls for an increase in the current bitrate, (2) the estimated available bitrate is higher than or equal to the maximum available bitrate multiplied by the first predetermined factor, and (3) the acceptable quality of experience for multimedia transmissions cannot be achieved with the current bitrate set to be equal to the minimum available bitrate.

27. The method of claim 22 further comprising:

setting, by the multimedia communications server, the current bitrate for the at least one video encoder to be equal to the estimated available bitrate for the respective multimedia participant device if (1) the estimated available bitrate calls for a decrease in the current bitrate, and (2) the estimated available bitrate is higher than the current bitrate multiplied by a second predetermined factor.

28. The method of claim 27 further comprising:

setting, by the multimedia communications server, the current bitrate for the at least one video encoder to be equal to the estimated available bitrate for the respective multimedia participant device if (1) the estimated available bitrate calls for a decrease in the current bitrate, (2) the estimated available bitrate is lower than or equal to the current bitrate multiplied by the second predetermined factor, and (3) an acceptable quality of experience for multimedia transmissions can be achieved with the current bitrate set to be equal to the estimated available bitrate.

29. A multimedia communications server for use in a multimedia communications system, the multimedia communications system including a plurality of multimedia participant devices communicably coupleable to the multimedia communications server over at least one network, the multimedia communications server comprising:

at least one video encoder; and

a controller including at least one processor operative to execute at least one program out of at least one memory;

to receive at least one report packet from a respective multimedia participant device, the at least one report packet containing packet error feedback information, the plurality of multimedia participant devices participating in a multimedia session and sharing operations of the same video encoder;

to determine whether the packet error feedback information includes one or more of a request for an intra-coded frame and an estimated available bandwidth of the respective multimedia participant device;

in the event the packet error feedback information includes the request for the intra-coded frame, to determine a first cost of sending the intra-coded frame to the plurality of multimedia participant devices participating in the multimedia session and sharing the operations of the same video encoder;

in the event the packet error feedback information includes the estimated available bandwidth of the respective multimedia participant device, to determine a second cost of adjusting an average bitrate employed in the multimedia session; and

based at least upon one or more of the first cost and the second cost, to perform one or more of sending the intra-coded frame to the plurality of multimedia participant devices and adjusting the average bitrate employed in the multimedia session.

30. The system of claim 46 wherein the at least one processor is further operative to execute the at least one program out of the at least one memory to determine the first cost of sending the intra-coded frame using a cost function of a plurality of cost factors, the plurality of cost factors including a number of additional bits required to encode a current frame using intra-coding as opposed to using inter-coding, and a total number of the plurality of multimedia participant devices sharing the operations of the at least one video encoder.