Constraint flags in general constraints information
A method of video encoding includes determining whether a plurality of constraint flags of a constraint information group are to be signaled for a subset of coding blocks, and signaling a gate flag indicating whether the plurality of constraint flags of the constraint information group are signaled. The gate flag is signaled in constraint information in a syntax structure of a coded video bitstream. In accordance with the signaled gate flag indicating that the plurality of constraint flags of the constraint information group are signaled, the method further includes signaling the plurality of constraint flags of the constraint information group in the constraint information in the syntax structure of the coded video bitstream. In accordance with the plurality of constraint flags being signaled in the constraint information, the method further includes encoding the subset of coding blocks based on the plurality of constraint flags.
1. A method of video encoding in an encoder, the method comprising:
determining whether each constraint information group of at least one constraint information group and including a plurality of constraint flags is to be signaled for a subset of coding blocks in constraint information in a video bitstream;
signaling, in the constraint information, a gate flag of each constraint information group indicating whether the respective constraint information group of the at least one constraint information group corresponding to the respective gate flag is signaled in the constraint information, the constraint information being for the subset of coding blocks in the video bitstream, each constraint information group including the respective plurality of constraint flags for the subset of coding blocks;
generating prediction information for the subset of coding blocks based on whether a first constraint information group in the at least one constraint information group is signaled in the constraint information;
based on whether the first constraint information group including the plurality of constraint flags is signaled in the constraint information, encoding the subset of coding blocks, wherein
when the first constraint information group of the gate flag is determined to be signaled in the constraint information,
the generating the prediction information includes generating the prediction information for the subset of coding blocks based on the plurality of constraint flags in the first constraint information group of the gate flag; and
an offset and a length are signaled in the constraint information indicating that the plurality of constraint flags in the first constraint information group of the gate flag is signaled in the constraint information.
2. The method of claim 1 , wherein
the plurality of constraint flags in the first constraint information group is determined to be signaled in the constraint information.
3. The method of claim 1 , wherein
a plurality of constraint flags of a second constraint information group in the at least one constraint information group is determined not to be signaled in the constraint information.
4. The method of claim 1 , wherein the gate flag of a second constraint information group in the at least one constraint information group indicates that a plurality of constraint flags of the second constraint information group in the at least one constraint information group is not signaled, and the plurality of constraint flags of the second constraint information group is not signaled in the constraint information.
5. The method of claim 1 , wherein the constraint information is a high level syntax structure for at least one picture, and the subset of coding blocks includes coding blocks in the at least one picture.
6. The method of claim 1 , wherein
the plurality of constraint flags in the first constraint information group is determined to be signaled,
the plurality of constraint flags is signaled according to a predetermined order, and
the method further includes
run-encoding the plurality of constraint flags; and
generating the prediction information for the subset of coding blocks based on the plurality of constraint flags.
7. The method of claim 2 , wherein
the plurality of constraint flags is signaled according to a predetermined order, and
the generating the prediction information further includes run-encoding the plurality of constraint flags.
8. The method of claim 2 , wherein
the at least one constraint information group includes plural constraint information groups and plural corresponding gate flags indicating presence of each of the plural constraint information groups, and
an offset and a length are signaled in the constraint information for each of the plural constraint information groups indicating a position of and a number of contiguous constraint flags in the respective one of the plural constraint information groups.
9. The method of claim 8 , wherein
a syntax element indicating a number of offsets included in the constraint information is signaled in the constraint information.
10. The method of claim 1 , wherein
one or more constraint information groups including the first constraint information group are signaled in the video bitstream, and
one or more syntax elements in the constraint information are byte aligned, the one or more syntax elements including the gate flag of each of the one or more constraint information groups and including the plurality of constraint flags in the one or more constraint information groups.
11. A method of video decoding, the method comprising:
obtaining a gate flag of each of at least one constraint information group in constraint information signaled in a coded video bitstream, each gate flag indicating whether a constraint information group of the at least one constraint information group corresponding to the respective gate flag is present in the constraint information, the constraint information being for a subset of coding blocks in the coded video bitstream;
determining whether a first constraint information group of the at least one constraint information group is present in the constraint information based on the gate flag of the first constraint information group of the at least one constraint information group, the first constraint information group including a plurality of constraint flags for the subset of coding blocks;
determining prediction information for the subset of coding blocks based on whether the first constraint information group of the gate flag is present in the constraint information; and
reconstructing the subset of coding blocks based on the prediction information, wherein
when the first constraint information group of the gate flag is determined to be present in the constraint information;
the determining the prediction information includes determining the prediction information for the subset of coding blocks based on the plurality of constraint flags in the first constraint information group of the gate flag; and
an offset and a length are present in the constraint information indicating that the plurality of constraint flags in the first constraint information group of the gate flag is present in the constraint information.
12. The method of claim 11 , wherein
the plurality of constraint flags in the first constraint information group is determined to be present in the constraint information.
13. The method of claim 11 , wherein
a plurality of constraint flags of a second constraint information group in the at least one constraint information group is determined not to be present in the constraint information.
14. The method of claim 11 , wherein the gate flag of a second constraint information group in the at least one constraint information group indicates that a plurality of constraint flags of the second constraint information group in the at least one constraint information group is not present in the constraint information, and the plurality of constraint flags of the second constraint information group is not present in the constraint information.
15. The method of claim 11 , wherein the constraint information is a high level syntax structure for at least one picture, and the subset of coding blocks includes coding blocks in the at least one picture.
16. The method of claim 11 , wherein
the plurality of constraint flags in the first constraint information group is determined to be present in the constraint information,
the plurality of constraint flags is signaled according to a predetermined order, and
the determining the prediction information further includes run-decoding the plurality of constraint flags and determining the prediction information for the subset of coding blocks based on the plurality of constraint flags.
17. The method of claim 12 , wherein
the plurality of constraint flags is signaled according to a predetermined order, and
the determining the prediction information further includes run-encoding the plurality of constraint flags.
18. The method of claim 12 , wherein
the at least one constraint information group includes plural constraint information groups and plural corresponding gate flags indicating presence of each of the plural constraint information groups, and
an offset and a length are present in the constraint information for each of the plural constraint information groups indicating a position of and a number of contiguous constraint flags in the respective one of the plural constraint information groups.
19. The method of claim 18 , wherein
a syntax element indicating a number of offsets included in the constraint information is present in the constraint information.
20. 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 gate flag of each constraint information group indicating whether the respective constraint information group of at least one constraint information group corresponding to the respective gate flag is present in constraint information, the constraint information being for a subset of coding blocks in the video bitstream, each constraint information group including respective plurality of constraint flags for the subset of coding blocks; and
the format rule specifies that:
each gate flag of a respective one of the at least one constraint information group in the constraint information signaled in the video bitstream is obtained;
whether a first constraint information group of the at least one constraint information group is present in the constraint information is determined based on the gate flag of the first constraint information group of the at least one constraint information group, the first constraint information group including a plurality of constraint flags for the subset of coding blocks; and
when the first constraint information group of the first gate flag is determined to be present in the constraint information,
an offset and a length are present in the constraint information indicating that the plurality of constraint flags in the first constraint information group of the gate flag is present in the constraint information;
prediction information for the subset of coding blocks is determined based on the plurality of constraint flags in the first constraint information group of the gate flag; and
the subset of coding blocks is reconstructed based on the prediction information.