Signaling of quantization information in coded video
View Patent ↗Examples of video encoding methods and apparatus and video decoding methods and apparatus are described. An example method of video processing includes performing a conversion between a current picture of a video and a bitstream of the video according to a rule. The rule specifies that the current picture is a recovery point picture in response to the current picture being a Gradual Decoding Refresh (GDR) picture with a recovery Picture Order Count (POC) value of 0. The recovery POC count specifies a recovery point of decoded pictures in an output order.
1. A method of processing video data, comprising:
performing a conversion between a video comprising a current video block and a bitstream of the video,
wherein a range of a value of a first syntax element specifying a number of points in a quantization parameter (QP) table associated with the conversion of the current video block is dependent on one or more other syntax elements comprising a second syntax element according to a rule,
wherein the rule specifies that the range of the value of the first syntax element is based on a value of the second syntax element specifying a starting luma and chroma QP used to describe the QP table, and
wherein a maximum allowed value of the first syntax element is equal to (K−the value of the second syntax element), K being a positive integer.
2. The method of claim 1 , wherein the QP table is an i-th chroma QP mapping table.
3. The method of claim 2 , wherein the second syntax element is represented as sps_qp_table_start_minus26[i] whose value plus 26 specifying the starting luma and chroma QP used to describe the i-th chroma QP mapping table.
4. The method of claim 3 , wherein the maximum allowed value of the first syntax element is equal to (36−sps_qp_table_start_minus26[i]).
5. The method of claim 1 , wherein the current video block is included in a current picture of the video, and
wherein the rule specifies that the current picture is a recovery point picture in response to the current picture being a gradual decoding refresh (GDR) picture with a recovery picture order count (POC) count of 0, and wherein the recovery POC count specifies a recovery point of decoded pictures in an output order.
6. The method of claim 1 , wherein the conversion comprises encoding the video into the bitstream.
7. The method of claim 1 , wherein the conversion comprises decoding the video from the bitstream.
8. 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 a current video block and a bitstream of the video,
wherein a range of a value of a first syntax element specifying a number of points in a quantization parameter (QP) table associated with the conversion of the current video block is dependent on one or more other syntax elements comprising a second syntax element according to a rule,
wherein the rule specifies that the range of the value of the first syntax element is based on a value of the second syntax element specifying a starting luma and chroma QP used to describe the QP table, and
wherein a maximum allowed value of the first syntax element is equal to (K−the value of the second syntax element), K being a positive integer.
9. The apparatus of claim 8 , wherein the QP table is an i-th chroma QP mapping table.
10. The apparatus of claim 9 , wherein K is equal to 36, and
wherein the second syntax element is represented as sps_qp_table_start_minus26[i] whose value plus 26 specifying the starting luma and chroma QP used to describe the i-th chroma QP mapping table.
11. The apparatus of claim 8 , wherein the current video block is included in a current picture of the video, and
wherein the rule specifies that the current picture is a recovery point picture in response to the current picture being a gradual decoding refresh (GDR) picture with a recovery picture order count (POC) count of 0, and wherein the recovery POC count specifies a recovery point of decoded pictures in an output order.
12. A non-transitory computer-readable storage medium storing instructions that cause a processor to:
perform a conversion between a video comprising a current video block and a bitstream of the video,
wherein a range of a value of a first syntax element specifying a number of points in a quantization parameter (QP) table associated with the conversion of the current video block is dependent on one or more other syntax elements comprising a second syntax element according to a rule,
wherein the rule specifies that the range of the value of the first syntax element is based on a value of the second syntax element specifying a starting luma and chroma QP used to describe the QP table, and
wherein a maximum allowed value of the first syntax element is equal to (K−the value of the second syntax element), K being a positive integer.
13. The non-transitory computer-readable storage medium of claim 12 , wherein the QP table is an i-th chroma QP mapping table.
14. The non-transitory computer-readable storage medium of claim 13 , wherein K is equal to 36, and
wherein the second syntax element is represented as sps_qp_table_start_minus26[i] whose value plus 26 specifying the starting luma and chroma QP used to describe the i-th chroma QP mapping table.
15. The non-transitory computer-readable storage medium of claim 12 , wherein the current video block is included in a current picture of the video, and
wherein the rule specifies that the current picture is a recovery point picture in response to the current picture being a gradual decoding refresh (GDR) picture with a recovery picture order count (POC) count of 0, and wherein the recovery POC count specifies a recovery point of decoded pictures in an output order.
16. 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 a current video block,
wherein a range of a value of a first syntax element specifying a number of points in a quantization parameter (QP) table associated with the current video block is dependent on one or more other syntax elements comprising a second syntax element according to a rule,
wherein the rule specifies that the range of the value of the first syntax element is based on a value of the second syntax element specifying a starting luma and chroma QP used to describe the QP table, and
wherein a maximum allowed value of the first syntax element is equal to (K−the value of the second syntax element), K being a positive integer.
17. The non-transitory computer-readable recording medium of claim 16 , wherein the QP table is an i-th chroma QP mapping table.
18. The non-transitory computer-readable recording medium of claim 17 , wherein K is equal to 36, and
wherein the second syntax element is represented as sps_qp_table_start_minus26[i] whose value plus 26 specifying the starting luma and chroma QP used to describe the i-th chroma QP mapping table.
19. The non-transitory computer-readable recording medium of claim 16 , wherein the current video block is included in a current picture of the video, and
wherein the rule specifies that the current picture is a recovery point picture in response to the current picture being a gradual decoding refresh (GDR) picture with a recovery picture order count (POC) count of 0, and wherein the recovery POC count specifies a recovery point of decoded pictures in an output order.