LOW-DELAY VIDEO BUFFERING IN VIDEO CODING

• US 20130266076A1
• Filed: 02/25/2013
• Published: 10/10/2013
• Est. Priority Date: 04/04/2012
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: WANG, Ye-Kui, CHEN, Ying
• Granted Patent: US 9,565,431 B2
• Time in Patent Office: Days
• US Class Current: 375/240.25
• CPC Class Codes: H04N 19/44 Decoders specially adapted therefor, e.g. video decoders which are asymmetric with respect to the encoder
• CPC Class Codes: H04N 19/46 Embedding additional information in the video signal during the compression process H04N19/517, H04N19/68, H04N19/70 take precedence
• CPC Class Codes: H04N 19/70 characterised by syntax aspects related to video coding, e.g. related to compression standards

Abstract

As one example, a method of coding video data includes storing one or more decoding units of video data in a coded picture buffer (CPB). The method further includes obtaining a respective buffer removal time for the one or more decoding units. The method further includes removing the decoding units from the CPB in accordance with the obtained buffer removal time for each of the decoding units. The method further includes determining whether the CPB operates at access unit level or sub-picture level. The method further includes coding video data corresponding to the removed decoding units. If the CPB operates at access unit level, coding the video data comprises coding access units comprised in the decoding units. If the CPB operates at sub-picture level, coding the video data comprises coding subsets of access units comprised in the decoding units.

Claims

1. A method of coding video data, the method comprising:

storing one or more decoding units of video data in a coded picture buffer (CPB);

obtaining a respective buffer removal time for the one or more decoding units;

removing the decoding units from the CPB in accordance with the obtained buffer removal time for each of the decoding units;

determining whether the CPB operates at access unit level or sub-picture level; and

coding video data corresponding to the removed decoding units,

wherein, if the CPB operates at access unit level, coding the video data comprises coding access units comprised in the decoding units; and

wherein, if the CPB operates at sub-picture level, coding the video data comprises coding subsets of access units comprised in the decoding units.

2. The method of claim 1, wherein determining whether the CPB operates at access unit level or sub-picture level comprises:

determining that the CPB operates at access unit level if a sub-picture coded picture buffer preferred flag has a value of zero or if a sub-picture coded picture buffer parameters present flag has a value of zero; and

determining that the CPB operates at sub-picture level if both the sub-picture coded picture buffer preferred flag has a value of one and the sub-picture coded picture buffer parameters present flag has a value of one.

3. The method of claim 2, further comprising receiving the value for the sub-picture coded picture buffer preferred flag.

4. The method of claim 2, further comprising setting a value of zero for the sub-picture coded picture buffer preferred flag if a value for the sub-picture coded picture buffer preferred flag is not received.

5. The method of claim 2, further comprising receiving the value for the sub-picture coded picture buffer parameters present flag.

6. The method of claim 1, further comprising:

receiving the one or more decoding units of video data in a continuous decoding order,

wherein storing the one or more decoding units of video data in the CPB comprises storing the one or more decoding units of video data in the continuous decoding order in the CPB.

7. The method of claim 1, wherein obtaining the respective buffer removal time for the one or more decoding units comprises receiving a respective signaled value indicative of the respective buffer removal time for at least one of the decoding units.

8. The method of claim 7, wherein the signaled value indicative of the buffer removal time for the at least one of the decoding units comprises a signaled value indicative of a number of network abstraction layer (NAL) units comprised by the at least one of the decoding units.

9. The method of claim 1, wherein the one or more decoding units comprise respective sub-pictures, the method further comprising receiving a signaled value indicative of a byte alignment of at least one sub-picture within a larger set of the video data.

10. A device for coding video data, the device comprising a video coder configured to:

store one or more decoding units of video data in a coded picture buffer (CPB);

obtain a respective buffer removal time for the one or more decoding units;

remove the decoding units from the CPB in accordance with the obtained buffer removal time for each of the decoding units;

determine whether the CPB operates at access unit level or sub-picture level; and

code video data corresponding to the removed decoding units,

wherein, if the CPB operates at access unit level, to code the video data, the video coder is further configured to code access units comprised in the decoding units; and

wherein, if the CPB operates at sub-picture level, to code the video data, the video coder is further configured to code subsets of access units comprised in the decoding units.

11. The device of claim 10, wherein, to determine whether the CPB operates at access unit level or sub-picture level, the video coder is further configured to:

determine that the CPB operates at access unit level if a sub-picture coded picture buffer preferred flag has a value of zero or if a sub-picture coded picture buffer parameters present flag has a value of zero; and

determine that the CPB operates at sub-picture level if both the sub-picture coded picture buffer preferred flag has a value of one and the sub-picture coded picture buffer parameters present flag has a value of one.

12. The device of claim 11, wherein the video coder is further configured to receive the value for the sub-picture coded picture buffer preferred flag.

13. The device of claim 11, wherein the video coder is further configured to set a value of zero for the sub-picture coded picture buffer preferred flag if a value for the sub-picture coded picture buffer preferred flag is not received.

14. The device of claim 11, wherein the video coder is further configured to receive the value for the sub-picture coded picture buffer parameters present flag.

15. The device of claim 10, wherein the video coder is further configured to:

receive the one or more decoding units of video data in a continuous decoding order,

wherein storing the one or more decoding units of video data in the CPB comprises storing the one or more decoding units of video data in the continuous decoding order in the CPB.

16. The device of claim 10, wherein obtaining the respective buffer removal time for the one or more decoding units comprises receiving a respective signaled value indicative of the respective buffer removal time for at least one of the decoding units.

17. The device of claim 16, wherein the signaled value indicative of the buffer removal time for the at least one of the decoding units comprises a signaled value indicative of a number of network abstraction layer (NAL) units comprised by the at least one of the decoding units.

18. The device of claim 10, wherein the one or more decoding units comprise respective sub-pictures, and the video coder is further configured to receiving a signaled value indicative of a byte alignment of at least one sub-picture within a larger set of the video data.

19. The device of claim 10, wherein the device comprises at least one of:

one or more integrated circuits;

one or more microprocessors; and

a wireless communication device that includes the video coder.

20. An apparatus for coding video data, the apparatus comprising:

means for storing one or more decoding units of video data in a coded picture buffer (CPB);

means for obtaining a respective buffer removal time for the one or more decoding units;

means for removing the decoding units from the CPB in accordance with the obtained buffer removal time for each of the decoding units;

means for determining whether the CPB operates at access unit level or sub-picture level; and

means for coding video data corresponding to the removed decoding units,

wherein, if the CPB operates at access unit level, the means for coding the video data comprises means for coding access units comprised in the decoding units; and

wherein, if the CPB operates at sub-picture level, the means for coding the video data comprises means for coding subsets of access units comprised in the decoding units.

21. The apparatus of claim 20, wherein the means for determining whether the CPB operates at access unit level or sub-picture level comprises:

means for determining that the CPB operates at access unit level if a sub-picture coded picture buffer preferred flag has a value of zero or if a sub-picture coded picture buffer parameters present flag has a value of zero; and

means for determining that the CPB operates at sub-picture level if both the sub-picture coded picture buffer preferred flag has a value of one and the sub-picture coded picture buffer parameters present flag has a value of one.

22. The apparatus of claim 21, further comprising means for receiving the value for the sub-picture coded picture buffer preferred flag.

23. The apparatus of claim 21, further comprising means for setting a value of zero for the sub-picture coded picture buffer preferred flag if a value for the sub-picture coded picture buffer preferred flag is not received.

24. The apparatus of claim 21, further comprising means for receiving the value for the sub-picture coded picture buffer parameters present flag.

25. The apparatus of claim 20, further comprising:

means for receiving the one or more decoding units of video data in a continuous decoding order,

wherein the means for storing the one or more decoding units of video data in the CPB comprises means for storing the one or more decoding units of video data in the continuous decoding order in the CPB.

26. The apparatus of claim 20, wherein the means for obtaining the respective buffer removal time for the one or more decoding units comprises means for receiving a respective signaled value indicative of the respective buffer removal time for at least one of the decoding units.

27. The apparatus of claim 26, wherein the signaled value indicative of the buffer removal time for the at least one of the decoding units comprises a signaled value indicative of a number of network abstraction layer (NAL) units comprised by the at least one of the decoding units.

28. The apparatus of claim 20, wherein the one or more decoding units comprise respective sub-pictures, the apparatus further comprising means for receiving a signaled value indicative of a byte alignment of at least one sub-picture within a larger set of the video data.

29. The apparatus of claim 20, wherein the apparatus comprises at least one of:

one or more integrated circuits;

one or more microprocessors; and

a wireless communication device that includes a video coding device.

30. A computer program product comprising a computer-readable storage medium comprising instructions stored thereon that, if executed, cause a processor to:

store one or more decoding units of video data in a coded picture buffer (CPB);

obtain a respective buffer removal time for the one or more decoding units;

remove the decoding units from the CPB in accordance with the obtained buffer removal time for each of the decoding units;

determine whether the CPB operates at access unit level or sub-picture level; and

code video data corresponding to the removed decoding units,

wherein, if the CPB operates at access unit level, coding the video data comprises coding access units comprised in the decoding units; and

wherein, if the CPB operates at sub-picture level, coding the video data comprises coding subsets of access units comprised in the decoding units.

31. The computer program product of claim 30, wherein determining whether the CPB operates at access unit level or sub-picture level comprises:

determining that the CPB operates at access unit level if a sub-picture coded picture buffer preferred flag has a value of zero or if a sub-picture coded picture buffer parameters present flag has a value of zero; and

determining that the CPB operates at sub-picture level if both the sub-picture coded picture buffer preferred flag has a value of one and the sub-picture coded picture buffer parameters present flag has a value of one.

32. The computer program product of claim 31, wherein the instructions further cause the processor to receive the value for the sub-picture coded picture buffer preferred flag.

33. The computer program product of claim 31, wherein the instructions further cause the processor to set a value of zero for the sub-picture coded picture buffer preferred flag if a value for the sub-picture coded picture buffer preferred flag is not received.

34. The computer program product of claim 31, wherein the instructions further cause the processor to receive the value for the sub-picture coded picture buffer parameters present flag.

35. The computer program product of claim 30, wherein the instructions further cause the processor to:

receive the one or more decoding units of video data in a continuous decoding order,

wherein storing the one or more decoding units of video data in the CPB comprises storing the one or more decoding units of video data in the continuous decoding order in the CPB.

36. The computer program product of claim 30, wherein obtaining the respective buffer removal time for the one or more decoding units comprises receiving a respective signaled value indicative of the respective buffer removal time for at least one of the decoding units.

37. The computer program product of claim 36, wherein the signaled value indicative of the buffer removal time for the at least one of the decoding units comprises a signaled value indicative of a number of network abstraction layer (NAL) units comprised by the at least one of the decoding units.

38. The computer program product of claim 30, wherein the one or more decoding units comprise respective sub-pictures, the method further comprising receiving a signaled value indicative of a byte alignment of at least one sub-picture within a larger set of the video data.