 between particular scalable layers indicated by the preceding scalability information SEI message are changed for a particular set of access units. In the following specification of this clause, the terms scalable layer, representation of a scalable layer, scalable layer representation, and primary coded VCL NAL unit are used as specified in clause G.13.2.1. A layer dependency change SEI message shall not be included in a scalable nesting SEI message. A layer dependency change SEI message shall not be present in an access unit that does not belong to the target access unit set of any scalability information SEI message. A layer dependency change SEI message shall not be succeeded, in decoding order, by a scalability information SEI message or a layers not present SEI message inside the same access unit. The set of access units consisting of the access unit associated with the layer dependency change SEI message and all succeeding access units in decoding order until, but excluding, the next access unit that contains a layer dependency change SEI message or a layers not present SEI message or that does not contain any primary coded VCL NAL units with IdrPicFlag equal to 0 (if present), or the end of the bitstream (otherwise) is referred to as the target access unit set. The layer dependency change SEI message applies to the target access unit set. Rec. ITU-T H.264 (01/2012) A layer dependency change 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 - Layer dependency change SEI messages do not have a cumulative effect. The presence of the layer dependency change SEI message specifies the following. For a sc