High-level constraint flag for local chroma quantization parameter control

Patent metadata

Field	Value
Publication number	US-12355964-B2
Application number	US-202117910047-A
Country	US
Kind code	B2
Filing date	Mar 8, 2021
Priority date	Mar 12, 2020
Publication date	Jul 8, 2025
Grant date	Jul 8, 2025

Abstract

A method and apparatus to improve compression efficiency in a video compression scheme enables separate control of a local chroma quantization parameter. The control can be used to disable a local chroma quantization parameter. One embodiment uses an existing local luma quantization parameter control flag for controlling local chroma quantization parameter. Another embodiment includes a separate local chroma quantization parameter control flag. Bitstream syntax is used to convey the flags.

First claim

The invention claimed is:

1. An apparatus, comprising:
a processor, configured to perform:
quantizing at least one video block based on at least one quantization parameter that is used for chroma quantization; and,
encoding said quantized at least one video block and syntax indicative of said at least one quantization parameter, and said syntax comprises a flag to disable local chroma quantization parameter control, wherein said syntax comprises a no_chroma_qp_offset_constraint_flag.

2. A method, comprising:
parsing a video bitstream for syntax used to control at least one quantization parameter that is used for chroma quantization for at least one coded video block; and,
decoding said at least one video block using the at least one quantization parameter based on the syntax, and said syntax comprises a flag to disable local chroma quantization parameter control, wherein said syntax comprises a no_chroma_qp_offset_constraint_flag.

3. The apparatus of claim 1 , wherein said syntax comprises a flag to control local luma quantization parameter control.

4. The apparatus of claim 1 , wherein said syntax comprises at least one flag to control local chroma quantization parameter control.

5. The apparatus of claim 1 wherein said syntax comprises a no_qp_delta_constraint_flag.

6. A method, comprising:
quantizing at least one video block based on at least one quantization parameter that is used for chroma quantization; and,
encoding said quantized at least one video block and syntax indicative of said at least one quantization parameter, wherein said syntax comprises a no_chroma_qp_offset_constraint_flag.

7. The apparatus of claim 1 , wherein said syntax corresponds to the High Efficiency Video Coding H.265 standard.

8. The apparatus of claim 1 , wherein said syntax corresponds to the Versatile Video Coding H.266 standard.

9. The apparatus of claim 1 , wherein said syntax is used for luma quantization control.

10. An apparatus, comprising:
a processor, configured to perform:
parsing a video bitstream for syntax used to control at least one quantization parameter that is used for chroma quantization for at least one coded video block; and,
decoding said at least one video block using the at least one quantization parameter based on the syntax, wherein said syntax comprises a no_chroma_qp_offset_constraint_flag.

11. A non-transitory computer readable medium containing data content generated according to the method of claim 1 , for playback using a processor.

12. A computer program product comprising instructions which, when the program is executed by a computer, cause the computer to carry out the method of claim 2 .

13. The method of claim 2 , wherein said syntax comprises a flag to control local luma quantization parameter control.

14. The method of claim 2 , wherein said syntax comprises at least one flag to control local chroma quantization parameter control.

15. The method of claim 2 , wherein said syntax comprises a no_qp_delta_constraint_flag.

16. A device comprising:
an apparatus according to claim 10 ; and
at least one of (i) an antenna configured to receive a signal, the signal including the video block, (ii) a band limiter configured to limit the received signal to a band of frequencies that includes the video block, and (iii) a display configured to display an output representative of a video block.

17. The apparatus of claim 10 , wherein said syntax corresponds to the High Efficiency Video Coding H.265 standard.

18. The apparatus of claim 10 , wherein said syntax corresponds to the Versatile Video Coding H.266 standard.

Assignees

• Interdigital Ce Patent Holdings Sas

Inventors

• De Lagrange Philippe
• Naser Karam
• Bordes Philippe
• Leleannec Fabrice

Classifications

• H04N19/70 Primary

  characterised by syntax aspects related to video coding, e.g. related to compression standards · CPC title

• H04N19/176

  the region being a block, e.g. a macroblock · CPC title

• H04N19/86

  involving reduction of coding artifacts, e.g. of blockiness · CPC title

• H04N19/124 Primary

  Quantisation · CPC title