POC value design for multi-layer video coding

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

decoding, by a video decoder, a first picture of a first layer of multi-layer video data, wherein the first picture has a first picture type;

based on the first picture having the first picture type, decoding, by the video decoder, data representative of picture order count (POC) most significant bits (MSB) value for the first picture;

determining a POC MSB delta value based on the data representative of the POC MSB value, the POC MSB delta value indicating an amount to decrement POC values of one or more pictures stored to a decoded picture buffer; and

decrementing the POC values of the one or more pictures stored to the decoded picture buffer by the POC MSB delta value.

2. The method of claim 1 , wherein decoding the data representative of the POC MSB value based on the first picture having the first picture type comprises:

determining whether the first picture type is included in a first set of picture types for which MSB values are coded or a second set of picture types for which MSB values are not coded; and

decoding the data representative of the POC MSB value for the picture only when the first picture type is included in the first set of picture types.

3. The method of claim 1 , further comprising, based on the data representative of the POC MSB for the first picture and without referencing a POC MSB value for a second picture of the multi-layer video data that precedes the first picture in coding order, determining the POC MSB for the first picture.

4. The method of claim 3 , further comprising constructing, by the video decoder, a reference picture list that includes the first picture having the determined POC MSB value.

5. The method of claim 1 , wherein the first picture type comprises at least one of a clean random access (CRA) picture or a broken link access (BLA) picture.

6. The method of claim 1 , wherein decoding the data representative of the POC MSB value for the first picture comprises decoding the data representative of the POC MSB value from a slice header extension.

7. The method of claim 1 , wherein decoding the data representative of the POC MSB value for the first picture comprises decoding a poc_msb_val syntax element.

8. The method of claim 1 , further comprising determining the first picture type based on a network abstraction layer (NAL) unit type of the first picture.

9. A method of encoding video data, the method comprising:

encoding, by a video encoder, a first picture of multi-layer video data, wherein the first picture has a first picture type; and

based on the first picture having the first picture type, encoding, by the video encoder, data representative of picture order count (POC) most significant bits (MSB) value for the first picture;

determining a POC MSB delta value based on the data representative of the POC MSB value, the POC MSB delta value indicating an amount to decrement POC values of one or more pictures stored to a decoded picture buffer; and

decrementing the POC values of the one or more pictures stored to the decoded picture buffer by the POC MSB delta value.

10. The method of claim 9 , wherein encoding the data representative of the POC MSB value based on the first picture having the first picture type comprises:

determining whether the first picture type is included in a first set of picture types for which MSB values are coded or a second set of picture types for which MSB values are not coded; and

encoding the data representative of the POC MSB value for the picture only when the first picture type is included in the first set of picture types.

11. The method of claim 9 , further comprising, based on the data representative of the POC MSB for the first picture and without referencing a POC MSB value for a second picture of the multi-layer video data that precedes the first picture in coding order, determining the POC MSB for the first picture.

12. The method of claim 11 , further comprising constructing, by the video encoder, a reference picture list that includes the first picture having the determined POC MSB value.

13. The method of claim 9 , wherein the first picture type comprises at least one of a clean random access (CRA) picture or a broken link access (BLA) picture.

14. The method of claim 9 , wherein encoding the data representative of the POC MSB value for the first picture comprises encoding the data representative of the POC MSB value in a slice header extension.

15. The method of claim 9 , wherein encoding the data representative of the POC MSB value for the first picture comprises decoding a poc_msb_val syntax element.

16. The method of claim 9 , further comprising determining the first picture type based on a network abstraction layer (NAL) unit type of the first picture.

17. A device for coding video data, the device comprising:

a memory configured to store multi-layer video data; and

a video coder configured to:

code a first picture of the multi-layer video data, wherein the first picture has a first picture type;

based on the first picture having the first picture type, code data representative of picture order count (POC) most significant bits (MSB) value for the first picture;

determine a POC MSB delta value based on the data representative of the POC MSB value, the POC MSB delta value indicating an amount to decrement POC values of one or more pictures stored to a decoded picture buffer; and

decrement the POC values of the one or more pictures stored to the decoded picture buffer by the POC MSB delta value.

18. The device of claim 17 , wherein to code the data representative of the POC MSB value based on the first picture having the first picture type, the video coder is configured to:

determine whether the first picture type is included in a first set of picture types for which MSB values are coded or a second set of picture types for which MSB values are not coded; and

code the data representative of the POC MSB value for the picture only when the first picture type is included in the first set of picture types.

19. The device of claim 17 , wherein the video coder is further configured to, based on the data representative of the POC MSB for the first picture and without referencing a POC MSB value for a second picture of the multi-layer video data that precedes the first picture in coding order, determine the POC MSB for the first picture.

20. The device of claim 19 , wherein the video coder is further configured to construct a reference picture list that includes the first picture having the determined POC MSB value.

21. The device of claim 17 , wherein the first picture type comprises at least one of a clean random access (CRA) picture or a broken link access (BLA) picture.

22. The device of claim 17 , wherein to code the data representative of the POC MSB value for the first picture, the video coder is configured to code the data representative of the POC MSB value from a slice header extension.

23. The device of claim 17 , wherein the device comprises at least one of:

an integrated circuit;

a microprocessor; or

a wireless communication device.

24. A device for coding video data, the device comprising:

means for coding a first picture of multi-layer video data, wherein the first picture has a first picture type;

means for coding, based on the first picture having the first picture type, data representative of picture order count (POC) most significant bits (MSB) value for the first picture;

means for determining a POC MSB delta value based on the data representative of the POC MSB value, the POC MSB delta value indicating an amount to decrement POC values of one or more pictures stored to a decoded picture buffer; and

means for decrementing the POC values of the one or more pictures stored to the decoded picture buffer by the POC MSB delta value.

25. The device of claim 24 , wherein the means for coding the data representative of the POC MSB value based on the first picture having the first picture type comprises:

means for determining whether the first picture type is included in a first set of picture types for which MSB values are coded or a second set of picture types for which MSB values are not coded; and

means for coding the data representative of the POC MSB value for the picture only when the first picture type is included in the first set of picture types.

26. The device of claim 24 , further comprising, based on the data representative of the POC MSB for the first picture and without referencing a POC MSB value for a second picture of the multi-layer video data that precedes the first picture in coding order, means for determining the POC MSB for the first picture.

27. The device of claim 26 , further comprising means for constructing a reference picture list that includes the first picture having the determined POC MSB value.

28. The device of claim 24 , wherein the first picture type comprises at least one of a clean random access (CRA) picture or a broken link access (BLA) picture.

29. The device of claim 24 , wherein the means for coding the data representative of the POC MSB value for the first picture comprises means for coding the data representative of the POC MSB value from a slice header extension.

30. A non-transitory computer-readable storage medium having stored thereon instructions that, when executed, cause a processor of a device for coding video data to:

code a first picture of multi-layer video data, wherein the first picture has a first picture type; and

based on the first picture having the first picture type, code data representative of picture order count (POC) most significant bits (MSB) value for the first picture;

determine a POC MSB delta value based on the data representative of the POC MSB value, the POC MSB delta value indicating an amount to decrement POC values of one or more pictures stored to a decoded picture buffer; and

decrement the POC values of the one or more pictures stored to the decoded picture buffer by the POC MSB delta value.

31. The non-transitory computer-readable storage medium of claim 30 , wherein to code the data representative of the POC MSB value based on the first picture having the first picture type, the instructions cause the processor to:

determine whether the first picture type is included in a first set of picture types for which MSB values are coded or a second set of picture types for which MSB values are not coded; and

code the data representative of the POC MSB value for the picture only when the first picture type is included in the first set of picture types.

32. The non-transitory computer-readable storage medium of claim 30 , wherein the instructions further cause the processor to, based on the data representative of the POC MSB for the first picture and without referencing a POC MSB value for a second picture of the multi-layer video data that precedes the first picture in coding order, determine the POC MSB for the first picture.

33. The non-transitory computer-readable storage medium of claim 32 , wherein the instructions further cause the processor to construct a reference picture list that includes the first picture having the determined POC MSB value.

34. The non-transitory computer-readable storage medium of claim 30 , wherein the first picture type comprises at least one of a clean random access (CRA) picture or a broken link access (BLA) picture.

35. The non-transitory computer-readable storage medium of claim 30 , wherein to code the data representative of the POC MSB value for the first picture, the instructions cause the processor to code the data representative of the POC MSB value from a slice header extension.