General constraints information for transform skip
Aspects of the disclosure provide methods and apparatuses for video data processing. In some examples, an apparatus for video data processing includes processing circuitry. For example, the processing circuitry determines a first syntax element for coding control in a first scope of coded video data in a bitstream. The first syntax element is associated with a coding tool of a slice based Rice coding for a residual coding in a transform skip mode. The coding tool provides a Rice parameter at a slice level for the residual coding in the transform skip mode. In response to the first syntax element being a first value indicative of disabling of the coding tool in the first scope, the processing circuitry decodes the first scope of coded video data that includes one or more second scopes of coded video data without invoking the coding tool.
1. A method of video decoding, comprising:
receiving a video bitstream, the video bitstream including a first syntax element corresponding to a general constraint information (GCI) syntax structure;
when the first syntax element indicates a first value:
decoding the GCI syntax structure and obtaining a second syntax element for coding control in a first scope of coded video data in the video bitstream, the second syntax element being associated with a coding tool of a slice based residual coding in a transform skip mode, the second syntax element indicating whether to disable the coding tool in each coded layer video sequence (CLVS) in the first scope of the coded video data;
when the second syntax element indicates a second value that is indicative of disabling of the coding tool in the first scope, decoding the first scope of the coded video data that includes one or more CLVSs of the coded video data without invoking the coding tool; and
wherein the second syntax element is denoted by general_no_ts_residual_coding_rice_present_in_sh_constraint_flag in general constraint information for coding control of pictures in an output layer set for a decoder.
2. The method of claim 1 , wherein the second value of the second syntax element is indicative of disabling the coding tool in each CLVS in the output layer set.
3. The method of claim 1 , further comprising:
when the second syntax element is the second value, constraining a third syntax element for coding control of a CLVS in the video bitstream to have a value indicative of no invoking of the coding tool for decoding the CLVS.
4. The method of claim 3 , wherein the value of the third syntax element indicates a nonexistence of a slice header flag associated with the coding tool in a slice header of a slice in a picture of the CLVS.
5. The method of claim 1 , further comprising:
when the second syntax element is a third value and the transform skip mode is enabled in a CLVS, determining a value of a third syntax element in a sequence parameter set (SPS) that the CLVS refers to, the third syntax element being indicative of a presenting/no presenting of a slice level syntax element indicating a selection of a Rice parameter.
6. The method of claim 5 , further comprising:
when the value of the third syntax element is indicative of a presenting of the slice level syntax element, decoding a fourth syntax element from a slice header of a slice, the fourth syntax element being indicative of the selection of the Rice parameter for the residual coding of the slice in the transform skip mode.
7. The method of claim 5 , wherein the determining the value of the third syntax element further comprises:
inferring, when the third syntax element is not present in the SPS for the CLVS, the value of the third syntax element for indicating the coding tool is not used in the CLVS.
8. A method of video encoding, comprising:
setting a first syntax element corresponding to a general constraint information (GCI) syntax structure;
when the first syntax element indicates a first value:
encoding the GCI syntax structure and a second syntax element for coding control in a first scope of coded video data in a video bitstream, the second syntax element being associated with a coding tool of a slice based residual coding in a transform skip mode, the second syntax element indicating whether the coding tool is disabled in each coded layer video sequence (CLVS) in the first scope of the coded video data;
when the second syntax element indicates a second value that is indicative of disabling of the coding tool in the first scope, encoding the first scope of the coded video data that includes one or more CLVSs of the coded video data in the video bitstream without invoking the coding tool; and
wherein the second syntax element is denoted by general_no_ts_residual_coding_rice_present_in_sh_constraint_flag in general constraint information for coding control of pictures in an output layer set for a decoder.
9. The method of claim 8 , wherein the second value of the second syntax element is indicative of disabling the coding tool in each CLVS in the output layer set.
10. The method of claim 8 , further comprising:
when the second syntax element is the second value, constraining a third syntax element for coding control of a CLVS in the video bitstream to have a value indicative of no invoking of the coding tool for decoding the CLVS.
11. The method of claim 10 , wherein the value of the third syntax element indicates a nonexistence of a slice header flag associated with the coding tool in a slice header of a slice in a picture of the CLVS.
12. The method of claim 8 , wherein:
when the second syntax element is a third value and the transform skip mode is enabled in a CLVS, encoding a value of a third syntax element in a sequence parameter set (SPS) that the CLVS refers to, the third syntax element being indicative of a presenting/no presenting of a slice level syntax element indicating a selection of a Rice parameter.
13. The method of claim 12 , further comprising:
when the value of the third syntax element is indicative of a presenting of the slice level syntax element, encoding a fourth syntax element in a slice header of a slice, the fourth syntax element being indicative of the selection of the Rice parameter for the residual coding of the slice in the transform skip mode.
14. The method of claim 12 , wherein, when the third syntax element is not present in the SPS for the CLVS, the value of the third syntax element is inferred to indicate the coding tool is not used in the CLVS.
15. A method of processing visual media data, the method comprising:
processing a video bitstream of the visual media data according to a format rule, wherein
the video bitstream includes a first syntax element corresponding to a general constraint information (GCI) syntax structure;
the format rule specifies that
when the first syntax element indicates a first value:
the GCI syntax structure is decoded and a second syntax element for coding control in a first scope of coded video data is obtained in the video bitstream, the second syntax element being associated with a coding tool of a slice based residual coding in a transform skip mode, the second syntax element indicating whether to disable the coding tool in each coded layer video sequence (CLVS) in the first scope of the coded video data,
when the second syntax element indicates a second value that is indicative of disabling of the coding tool in the first scope, the first scope of the coded video data that includes one or more CLVSs of the coded video data is decoded without invoking the coding tool; and
the second syntax element is denoted by general_no_ts_residual_coding_rice_present_in_sh_constraint_flag in general constraint information for coding control of pictures in an output layer set for a decoder.
16. The method of claim 15 , wherein the second value of the second syntax element is indicative of disabling the coding tool in each CLVS in the output layer set.
17. The method of claim 15 , wherein the format rule specifies that:
when the second syntax element is the second value, a third syntax element for coding control of a CLVS in the video bitstream is constrained to have a value indicative of no invoking of the coding tool for decoding the CLVS.