A method of decoding video data, the method comprising: decapsulating a slice of a random access point, RAP, picture of a bitstream from a network abstraction layer, NAL, unit, wherein the NAL unit includes a NAL unit type value that indicates whether the RAP picture is an instantaneous decoder refresh, IDR, picture and also indicates whether the RAP picture is a type of RAP picture that may have associated leading pictures that are decodable leading pictures, DLPs, wherein each leading picture follows a random access picture in decoding order and precedes the random access picture in output order and wherein the NAL unit type value being a first NAL unit type value indicates that the RAP picture is an IDR picture that may have associated DLPs and wherein the NAL unit type value being a second NAL unit type value indicates that the RAP picture is an IDR picture that does not have associated DLPs; determining that the RAP picture is an IDR picture that may have associated DLPs based on the NAL unit type value being the first NAL unit type value or that the RAP picture is an IDR picture that does not have associated DLPs based on the NAL unit type value being the second NAL unit type value; decoding the RAP picture and video data of the bitstream following the RAP picture based on the NAL unit type value; determining, for a subsequent NAL unit, that a NAL unit type value indicates that the subsequent NAL unit comprises a suffix supplemental enhancement information, SEI, NAL unit including a suffix SEI message wherein the suffix SEI NAL unit succeeds, in decoding order, the last video coding layer, VCL, NAL unit in an access unit, AU. decapsulating a slice of a random access point, RAP, picture of a bitstream from a network abstraction layer, NAL, unit, wherein the NAL unit includes a NAL unit type value that indicates whether the RAP picture is an instantaneous decoder refresh, IDR, picture and also indicates whether the RAP picture is a type of RAP picture that may have associated leading pictures that are decodable leading pictures, DLPs, wherein each leading picture follows a random access picture in decoding order and precedes the random access picture in output order and wherein the NAL unit type value being a first NAL unit type value indicates that the RAP picture is an IDR picture that may have associated DLPs and wherein the NAL unit type value being a second NAL unit type value indicates that the RAP picture is an IDR picture that does not have associated DLPs; determining that the RAP picture is an IDR picture that may have associated DLPs based on the NAL unit type value being the first NAL unit type value or that the RAP picture is an IDR picture that does not have associated DLPs based on the NAL unit type value being the second NAL unit type value; decoding the RAP picture and video data of the bitstream following the RAP picture based on the NAL unit type value; determining, for a subsequent NAL unit, that a NAL unit type value indicates that the subsequent NAL unit comprises a suffix supplemental enhancement information, SEI, NAL unit including a suffix SEI message wherein the suffix SEI NAL unit succeeds, in decoding order, the last video coding layer, VCL, NAL unit in an access unit, AU.