Signaling of general constrain information
Methods, systems, and devices for signaling of general constraint information are described. An example method of video processing includes performing a conversion between a video including one or more pictures and a bitstream of the video according to a rule. The rule specifies that a syntax structure in a profile-tier-level syntax structure is after a syntax element. The syntax structure includes information related to general constraint information (GCI) for the bitstream. The syntax element indicates a level to which an output layer set associated with the profile-tier-level syntax structure conforms.
1. A method of video processing, comprising:
performing a conversion between a video comprising one or more pictures and a bitstream of the video according to a first rule,
wherein the first rule specifies that a first general constraint information (GCI) syntax element is included at a beginning of a GCI syntax structure in a profile-tier-level syntax structure,
wherein the first GCI syntax element indicates whether one or more GCI syntax elements are included in the GCI syntax structure, and
wherein when the first GCI syntax element equaling zero indicates that the one or more GCI syntax elements are not included in the GCI syntax structure, the GCI syntax structure does not impose a constraint.
2. The method of claim 1 , wherein the conversion is performed further according to a second rule, and
wherein the second rule specifies that a second GCI syntax element indicating a number of reserved GCI bits is included in the bitstream.
3. The method of claim 2 , wherein the second rule further specifies that a value of each of the reserved GCI bits is included in the bitstream.
4. The method of claim 3 , wherein the value of each of the reserved GCI bits is coded as an unsigned 1-bit integer.
5. The method of claim 2 , wherein the second GCI syntax element is gci_num_reserved bits.
6. The method of claim 1 , wherein the conversion is performed further according to a third rule,
wherein the third rule specifies that the GCI syntax structure is after a syntax element, and
wherein the syntax structure comprises information related to GCI for the bitstream.
7. The method of claim 6 , wherein information related to GCI indicates whether one or more GCI flags are indicated, and/or one or more values of the one or more GCI flags.
8. The method of claim 6 , wherein the GCI syntax structure is a general_constraint_info( ) syntax structure and the syntax element is a general_level_idc syntax element.
9. The method of claim 1 , wherein the one or more GCI syntax elements exclude a byte alignment field.
10. An apparatus for processing video data comprising a processor and a non-transitory memory with instructions thereon, wherein the instructions upon execution by the processor, cause the processor to:
perform a conversion between a video comprising one or more pictures and a bitstream of the video according to a first rule,
wherein the first rule specifies that a first general constraint information (GCI) syntax element is included at a beginning of a GCI syntax structure in a profile-tier-level syntax structure,
wherein the first GCI syntax element indicates whether one or more GCI syntax elements are included in the GCI syntax structure, and
wherein when the first GCI syntax element equaling zero indicates that the one or more GCI syntax elements are not included in the GCI syntax structure, the GCI syntax structure does not impose a constraint.
11. The apparatus of claim 10 , wherein the conversion is performed according to a second rule,
wherein the second rule specifies that a second GCI syntax element indicating a number of reserved GCI bits is included in the bitstream.
12. The apparatus of claim 10 , wherein the conversion is performed further according to a third rule,
wherein the third rule specifies that the GCI syntax structure is after a syntax element, and
wherein the syntax structure comprises information related to general constraint information (GCI) for the bitstream.
13. The apparatus of claim 10 , wherein information related to GCI indicates whether one or more GCI flags are indicated, and/or one or more values of the one or more GCI flags.
14. The apparatus of claim 10 , wherein the GCI syntax structure is a general_constraint_info( ) syntax structure and the syntax element is a general_level_idc syntax element.
15. A non-transitory computer-readable storage medium storing instructions that cause a processor to:
perform a conversion between a video comprising one or more pictures and a bitstream of the video according to a first rule,
wherein the first rule specifies that a first general constraint information (GCI) syntax element is included at a beginning of a GCI syntax structure in a profile-tier-level syntax structure,
wherein the first GCI syntax element indicates whether one or more GCI syntax elements are included in the GCI syntax structure, and
wherein when the first GCI syntax element equaling zero indicates that the one or more GCI syntax elements are not included in the GCI syntax structure, the GCI syntax structure does not impose a constraint.
16. The non-transitory computer-readable storage medium of claim 15 , wherein the conversion is performed according to a second rule, wherein the second rule specifies that a second GCI syntax element indicating a number of reserved GCI bits is included in the bitstream.
17. The non-transitory computer-readable storage medium of claim 15 , wherein the conversion is performed further according to a third rule,
wherein the third rule specifies that the GCI syntax structure is after a syntax element, and
wherein the syntax structure comprises information related to general constraint information (GCI) for the bitstream.
18. The non-transitory computer-readable storage medium of claim 17 , wherein information related to GCI indicates whether one or more GCI flags are indicated, and/or one or more values of the one or more GCI flags.
19. A non-transitory computer-readable recording medium storing a bitstream of a video which is generated by a method performed by a video processing apparatus, wherein the method comprises:
generating the bitstream of the video comprising one or more pictures according to a first rule,
wherein the first rule specifies that a first general constraint information (GCI) syntax element is included at a beginning of a GCI syntax structure in a profile-tier-level syntax structure,
wherein the first GCI syntax element indicates whether one or more GCI syntax elements are included in the GCI syntax structure, and
wherein when the first GCI syntax element equaling zero indicates that the one or more GCI syntax elements are not included in the GCI syntax structure, the GCI syntax structure does not impose a constraint.
20. The non-transitory computer-readable recording medium of claim 19 , wherein the bitstream is generated according to a second rule
wherein the second rule specifies that a second GCI syntax element indicating a number of reserved GCI bits is included in the bitstream.