FIELD: information technology.SUBSTANCE: method for video data decoding contains decoding from the bit stream of the first network abstraction layer (NAL) level unit of video coding level (VCL) in order to decode in an access unit wherein the access unit includes video data to restore at least one image; decoding from the bit stream of the second VCL NAL unit in order to decode in the access unit; decoding from the bit stream of message with supplemental enhancement information (SEI) of some specific type in the access unit before decoding from the bit stream of the said first VCL NAL unit. Messages with SEI contain information related to video data processing; and decoding from the bit stream of copies of message with SEI of a particular type in the access unit after the decoding from the bit stream of the NAL VCL first unit and prior to decoding from the bit stream of the second NAL VCL unit. Contents of this copy of message with SEI of a particular type in the bit stream is limited to be identical to content of the decoded messages with SEI of a particular type.EFFECT: sustainability.20 cl 8 dwg 5 tbl