ccess unit set. The layers not present SEI message applies to the target access unit set. A layers not present SEI message refers to the most recent scalability information SEI message in decoding order. Each scalable layer that is referred to in this clause is a scalable layer indicated in the most recent scalability information SEI message in decoding order. Each layer identifier for a scalable layer that is referred to in this clause is a layer identifier for a scalable layer indicated in the most recent scalability information SEI message in decoding order. NOTE 1 - Layers not present SEI messages do not have a cumulative effect. num_layers specifies the number of syntax elements layer id[ i ] that are present in the layers not present SEI message. The value of num_layers shall be in the range of 0 to 2047, inclusive. layer_id[ i ] indicates the layer identifier of a scalable layer for which no VCL NAL units are present in the target access unit set. The value of layer id| i shall be in the range of 0 to 2047, inclusive. The value of layer_id[ i ] shall be equal to one of the values of layer id| i in the most recent scalability information SEI message. The target access unit set shall not contain any VCL NAL unit of the scalable layer having a layer identifier equal to layer_id[i]. When i is greater than 0, the value of layer_id[ i shall not be equal to any of the values of layer_id[ ] with j = - 1). NOTE 2 - When an application removes NAL units from a scalable bitstream, e.g. in order to adapt the bitstream to a transmission channel or the capabilities of a receiving device, and keeps the present layers not present SEI messages, it might need to modify the content of some of the layers not present SEI messages and remove some other layers not present SEI messages in order to obtain a bitstream conforming to this Recommendation | International Standard. G.13.2.6 Layer dependency change SEI message semantics The layer dependency change SEI message provides a mechanism for signalling that the interdependencies