High-level constraint flag for local chroma quantization parameter control
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.
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.