flag equal to 0 specifies that colour_primaries, transfer_characteristics and matrix_coefficients are not present. colour primaries indicates the chromaticity coordinates of the source primaries as specified in Table E-3 in terms of the CIE 1931 definition of X and y as specified by ISO 11664-1. When the colour primaries syntax element is not present, the value of colour_primaries shall be inferred to be equal to 2 (the chromaticity is unspecified or is determined by the application). Rec. ITU-T H.264 (01/2012) Table E-3 - Colour primaries Value Primaries Informative Remark Reserved For future use by ITU-T ISO/IEC primary ITU-R Rec. BT.709-5 green 0.300 0.600 ITU-R Rec. BT.1361 conventional colour gamut 0.150 0.060 system and extended colour gamut system 0.640 0.330 IEC 61966-2-4 white D65 0.3127 0.3290 Society of Motion Picture and Television Engineers RP 177 (1993) Annex B Unspecified Image characteristics are unknown or are determined by the application. Reserved For future use by ITU-T ISO/IEC primary ITU-R Rec. BT.470-6 System M (historical) green United States National Television System Committee 1953 Recommendation for transmission standards for colour television white C 0.310 0.316 United States Federal Communications Commission Title 47 Code of Federal Regulations (2003) 73.682 (a) (20) primary ITU-R Rec. BT.470-6 System B, G (historical) green ITU-R Rec. BT.601-6 625 ITU-R Rec. BT.1358 625 ITU-R Rec. BT.1700 625 PAL and 625 SECAM white D65 0.3127 0.3290 primary ITU-R Rec. BT.601-6 525 green 0.310 0.595 ITU-R Rec. BT.1358 525 0.155 0.070 ITU-R Rec. BT.1700 NTSC 0.630 0.340 Society of Motion Picture and Television white D65 0.3127 0.3290 Engineers 170M (2004) (functionally the same as the value 7) primary Society of Motion Picture and Television green 0.310 0.595 Engineers 240M (1999) 0.155 0.070 (functionally the same as the value 6) 0.630 0.340 white D65 0.3127 0.3290 primary Generic film (colour filters using Illuminant C) green 0.243 0.692 (Wratten 58) 0.145 0.049 (Wratten 47) 0.681 0.319 (Wratten 25)