Cross random access point signaling enhancements

1 . A method for processing video data comprising:

determining one or more random access point (RAP) picture identifiers for one or more Cross RAP Referencing (CRR) pictures; and

performing a conversion between a visual media data and a bitstream based on the one or more RAP picture identifiers;

wherein each of the CRR pictures is associated with an intra random access point (IRAP) picture, and wherein the IRAP picture is associated with a RAP picture identifier of zero; and

wherein the one or more RAP picture identifiers are different for each of the CRR pictures that are associated with a same IRAP picture.

2 . The method of claim 1 , wherein the one or more RAP picture identifiers are each coded in a coded layer video sequence minus one (t2drap_rap_id_in_clvs_minus1) field.

3 . The method of claim 1 , wherein the one or more RAP picture identifiers are each included in a type 2 dependent random access point (DRAP) supplemental enhancement information (SEI) message.

4 . The method of claim 2 , wherein each of the one or more RAP picture identifiers is specified by a value of the t2drap_rap_id_in_clvs_minus1 field plus one.

5 . The method of claim 1 , wherein the one or more RAP picture identifiers for each of the CRR pictures are set to a value greater than zero.

6 . The method of claim 1 , wherein a RAP picture identifier of the IRAP picture is inferred to be zero and is not signaled.

7 . The method of claim 1 , wherein the one or more RAP picture identifiers are denoted as RapPicIds.

8 . The method of claim 1 , wherein other syntax elements in a type 2 dependent random access point (DRAP) supplemental enhancement information (SEI) message are only signaled when a RAP picture identifier in the type 2 DRAP SEI message is greater than zero.

9 . The method of claim 1 , wherein the CRR pictures are denoted as type 2 dependent random access point (DRAP) pictures.

10 . The method of claim 1 , wherein the CRR pictures are denoted as enhanced dependent random access point (EDRAP) pictures.

11 . The method of claim 1 , wherein the conversion comprises generating the bitstream according to the visual media data.

12 . The method of claim 1 , wherein the conversion comprises parsing the bitstream to obtain the visual media data.

13 . 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:

determine one or more random access point (RAP) picture identifiers for one or more Cross RAP Referencing (CRR) pictures; and

perform a conversion between a visual media data and a bitstream based on the one or more RAP picture identifiers;

wherein each of the CRR pictures is associated with an intra random access point (IRAP) picture, and wherein the IRAP picture is associated with a RAP picture identifier of zero; and

wherein the one or more RAP picture identifiers are different for each of the CRR pictures that are associated with a same IRAP picture.

14 . The apparatus of claim 13 , wherein the one or more RAP picture identifiers are each coded in a coded layer video sequence minus one (t2drap_rap_id_in_clvs_minus1) field,

wherein the one or more RAP picture identifiers are each included in a type 2 dependent random access point (DRAP) supplemental enhancement information (SEI) message, and

wherein each of the one or more RAP picture identifiers is specified by a value of the t2drap_rap_id_in_clvs_minus1 field plus one.

15 . The apparatus of claim 13 , wherein the one or more RAP picture identifiers for each of the CRR pictures are set to a value greater than zero, and

wherein a RAP picture identifier of the IRAP picture is inferred to be zero and is not signaled.

16 . A non-transitory computer-readable storage medium storing instructions that cause a processor to:

determine one or more random access point (RAP) picture identifiers for one or more Cross RAP Referencing (CRR) pictures; and

perform a conversion between a visual media data and a bitstream based on the one or more RAP picture identifiers;

wherein each of the CRR pictures is associated with an intra random access point (IRAP) picture, and wherein the IRAP picture is associated with a RAP picture identifier of zero; and

wherein the one or more RAP picture identifiers are different for each of the CRR pictures that are associated with a same IRAP picture.

17 . The non-transitory computer-readable storage medium of claim 16 , wherein the one or more RAP picture identifiers are each coded in a coded layer video sequence minus one (t2drap_rap_id_in_clvs_minus1) field,

wherein the one or more RAP picture identifiers are each included in a type 2 dependent random access point (DRAP) supplemental enhancement information (SEI) message, and

wherein each of the one or more RAP picture identifiers is specified by a value of the t2drap_rap_id_in_clvs_minus1 field plus one.

18 . The non-transitory computer-readable storage medium of claim 16 , wherein the one or more RAP picture identifiers for each of the CRR pictures are set to a value greater than zero, and

wherein a RAP picture identifier of the IRAP picture is inferred to be zero and is not signaled.