FIELD: information technology.SUBSTANCE: device for determining the correspondence of a bitstream comprising: a buffer of coded pictures (CPB); and one or more processors configured to: receive an encoded video bitstream that includes an additional buffering period extension (SEI) message. SEI messages of the buffering period are subject to restriction that no SEI message of the buffering period in the bitstream can be associated with an access unit (AU) with TemporalId greater than 0 wherein the buffering period SEI provides information on the initial deletion delay from the CPB and the offset initial delete delay from the CPB the buffering period SEI contains an initial delete syntax element from the CPB for the plan selection index. The initial delete syntax element of the CPB is an element of the syntax of the alternative initial delete delay from the CPB for the plan selection index the hypothetical reference decoder (HRD) includes the CPB buffer and the decoded picture buffer (DPB) where the correspondence of the bit stream is specified as part of the HRD specification wherein the HRD relies on the buffering period SEI message the picture timing signal SEI the HRD parameters provided in the bitstream in the hrd_parameters() syntax structure in the video parameter set (VPS) or a sequence parameter set (SPS) the bitstream represents the video coded slice blocks of the video picture and the associated syntax elements the picture having a TemporalId of 1; And set the initial delete delay variable value from the CPB for the plan selection index to the syntax element of the initial delete delay from the CPB for the plan selection index when the DefaultInitCpbParamsFlag is 0.EFFECT: providing error-tolerant and effective signalling and removing the time to remove encoded pictures of encoded data units from the buffer when encoding video.8 cl 16 dwg 4 tbl