S is given by Sy = =(alphaFwt*fy)/alphaRange SCb = =(alphaFwtfcb)/alphaRange SCr = alphaFwt * for ) / alphaRange Pre-multiplied-black video has the characteristic that the picture S will appear correct if displayed against a black background. For a non-black background B, the composition of the displayed picture D may be calculated as =Sy+ alphaBwt by + alphaRange / / alphaRange dcb=scb+ ( alphaBwt * bcb + alphaRange / alphaRange dcr=scr + ( alphaBwt bcr + alphaRange 2) / alphaRange When aux format idc is equal to 2, S would be the decoded picture obtained from the decoded luma and chroma, and A would again be the decoded picture obtained from the decoded auxiliary coded picture. In this case, alpha blending composition does not involve multiplication of the samples of S by factors obtained from the samples of A. additional_extension_flag equal to 0 indicates that no additional data follows within the sequence parameter set extension syntax structure prior to the RBSP trailing bits. The value of additional_extension_flagshall be equal to 0. The value of 1 for additional_extension_flagi is reserved for future use by ITU-T ISO/IEC. Decoders shall ignore all data that follows the value of 1 for additional_extension_flag in a sequence parameter set extension NAL unit. 7.4.2.1.3 Subset sequence parameter set RBSP semantics svC_vui_parameters_present_flagequal to 0 specifies that the syntax structure SVC_vui_parameters_extension() is not present. vC_vui_parameters_present_flag equal to 1 specifies that the syntax structure SVC_vui_parameters_extension() is present. bit_equal_to_oneshall be equalto 1. mvc_vui_parameters_present_flag equal to 0 specifies that the syntax structure mvc_vui_parameters_extension() is not present. mv_vui_parameters_present_flag equal to 1 specifies that the syntax structure mvc_vui_parameters_extension() is present. additional_extension2_flag equal to 0 specifies that no additional_extension2_data_flag syntax elements are present in the subset sequence parameter set RBSP syntax structure. add