Granted Patent B2

US 12,356,013 · App. 17/984,861 · Granted Jul 8, 2025

Inventors: Byeongdoo Choi (Palo Alto, CA); Stephan Wenger (Hillsborough, CA); Shan Liu (San Jose, CA)

Assignee: TENCENT AMERICA LLC

H04N19/70H04N19/172H04N19/46H04N19/50

Abstract

Claims (55)

1. A method performed by at least one processor, the method comprising:

receiving a coded bitstream that includes an access unit (AU), the AU including a picture unit (PU) that includes:

a picture header network abstraction layer (NAL) unit that is a dependent picture header NAL unit, and

at least one video coding layer (VCL) NAL unit that is after the picture header NAL unit within the AU;

obtaining an independent picture header NAL unit of a coded picture of a reference layer, the coded picture of the reference layer being referenced by an enhancement layer picture that includes the at least one VCL NAL unit;

obtaining the dependent picture header NAL unit of the enhancement layer picture; and

performing picture header prediction comprising predicting a value of a syntax element of the dependent picture header NAL unit based on a value of a syntax element of the independent picture header NAL unit,

wherein the independent picture header NAL unit and the dependent picture header NAL unit are each an NAL unit that includes a NAL unit type syntax element that has a value indicating a picture header NAL unit.

2. The method of claim 1 , further comprising:

determining a delta value between the value of the syntax element of the dependent picture header NAL unit and the value of the syntax element of the independent picture header NAL unit.

3. The method of claim 1 , further comprising:

determining that the coded picture of the reference layer includes the independent picture header NAL unit based on a flag of the independent picture header NAL unit; and

determining that the enhancement layer picture includes the dependent picture header NAL unit based on a flag of the dependent picture header NAL unit.

4. The method of claim 1 , further comprising:

determining that the coded picture of the reference layer includes the independent picture header NAL unit based on a unit type of the coded picture of the reference layer; and

determining that the enhancement layer picture includes the dependent picture header NAL unit based on a unit type of the enhancement layer picture.

5. The method of claim 1 , wherein the independent picture header NAL unit directly precedes a VCL NAL unit in a decoding order in the coded picture of the reference layer.

6. The method of claim 1 , wherein the dependent picture header NAL unit directly precedes the at least one VCL NAL unit in a decoding order in the enhancement layer picture.

7. The method of claim 1 , wherein each of the coded picture in the reference layer and the enhancement layer picture includes a plurality of VCL NAL units and a plurality of picture header NAL units directly preceding the plurality of VCL NAL units, the plurality of VCL NAL units in the enhancement layer picture including the at least one VCL NAL unit in the enhancement layer picture.

8. A method of encoding, the method comprising:

encoding a bitstream that includes an access unit (AU), the AU including a picture unit (PU) that includes:

a picture header network abstraction layer (NAL) unit that is a dependent picture header NAL unit, and

at least one video coding layer (VCL) NAL unit that is after the picture header NAL unit within the AU; and

encoding an independent picture header NAL unit of a picture of a reference layer, the picture of the reference layer being referenced by an enhancement layer picture that includes the at least one VCL NAL unit, wherein

a value of a syntax element of the dependent picture header NAL unit of the enhancement layer picture is based on a value of a syntax element of the independent picture header NAL unit, and

the independent picture header NAL unit and the dependent picture header NAL unit are each an NAL unit that includes a NAL unit type syntax element that has a value indicating a picture header NAL unit.

9. The method of claim 8 , further comprising:

encoding, in the bitstream, a delta value between the value of the syntax element of the dependent picture header NAL unit and the value of the syntax element of the independent picture header NAL unit.

10. The method of claim 8 , further comprising:

encoding a flag of the independent picture header NAL unit that indicates the picture of the reference layer includes the independent picture header NAL unit; and

encoding a flag of the dependent picture header NAL unit that indicates the enhancement layer picture includes the dependent picture header NAL unit.

11. The method of claim 8 , further comprising:

encoding a unit type of the picture of the reference layer that indicates the picture of the reference layer includes the independent picture header NAL unit; and

encoding a unit type of the enhancement layer picture that indicates the enhancement layer picture includes the dependent picture header NAL unit.

12. The method of claim 8 , wherein the independent picture header NAL unit directly precedes a VCL NAL unit in an encoding order in the picture of the reference layer.

13. The method of claim 8 , wherein the dependent picture header NAL unit directly precedes the at least one VCL NAL unit in an encoding order in the enhancement layer picture.

14. The method of claim 8 , wherein each of the picture in the reference layer and the enhancement layer picture includes a plurality of VCL NAL units and a plurality of picture header NAL units directly preceding the plurality of VCL NAL units, the plurality of VCL NAL units in the enhancement layer picture including the at least one VCL NAL unit in the enhancement layer picture.

15. A method of processing visual media data, the method comprising:

processing a bitstream of the visual media data according to a format rule, wherein

the bitstream includes an access unit (AU), the AU including a picture unit (PU) that includes:

a picture header network abstraction layer (NAL) unit that is a dependent picture header NAL unit, and

at least one video coding layer (VCL) NAL unit that is after the picture header NAL unit within the AU; and

the format rule specifies that:

an independent picture header NAL unit of a coded picture of a reference layer is obtained, the coded picture of the reference layer being referenced by an enhancement layer picture that includes the at least one VCL NAL unit;

the dependent picture header NAL unit of the enhancement layer picture is obtained; and

picture header prediction is performed in which a value of a syntax element of the dependent picture header NAL unit is predicted based on a value of a syntax element of the independent picture header NAL unit, the independent picture header NAL unit and the dependent picture header NAL unit each being an NAL unit that includes a NAL unit type syntax element that has a value indicating a picture header NAL unit.

16. The method of claim 15 , wherein the format rule specifies that a delta value between the value of the syntax element of the dependent picture header NAL unit and the value of the syntax element of the independent picture header NAL unit is determined.

17. The method of claim 15 , wherein the format rule specifies that:

the coded picture of the reference layer is determined to include the independent picture header NAL unit based on a flag of the independent picture header NAL unit; and

the enhancement layer picture is determined to include the dependent picture header NAL unit based on a flag of the dependent picture header NAL unit.

18. The method of claim 15 , wherein the format rule specifies that:

the coded picture of the reference layer is determined to include the independent picture header NAL unit based on a unit type of the coded picture of the reference layer; and

the enhancement layer picture is determined to include the dependent picture header NAL unit based on a unit type of the enhancement layer picture.

19. The method of claim 15 , wherein the independent picture header NAL unit directly precedes a VCL NAL unit in a decoding order in the coded picture of the reference layer.

20. The method of claim 15 , wherein the dependent picture header NAL unit directly precedes the at least one VCL NAL unit in a decoding order in the enhancement layer picture.

Assignments (1)

Continuity (5)

References Cited (28)