Quicktime File Format (2012-08-14).pdf

Media Data Atom TypesVideo MediaY´ is an unsigned integer. Cb and Cr are offset binary integers.Certain Y´, Cb, and Cr component values v are reserved as synchronization signals and must not appear in abuffer. For n = 8 bits, these are values 0 and 255. For n = 10 bits, these are values 0, 1, 2, 3, 1020, 1021, 1022,and 1023. The writer of a QuickTime image is responsible for omitting these values. The reader of a QuickTimeimage may assume that they are not present.The remaining component values that fall outside the mapping for scheme B (1 to 15 and 241 to 254 for n =8 bits and 4 to 63 and 961 to 1019 for n = 10 bits) accommodate occasional filter undershoot and overshootin image processing. In some applications, these values are used to carry other information (e.g., transparency).The writer of a QuickTime image may use these values and the reader of a QuickTime image must expect thesevalues.The following tables show the primary values, transfer functions, and matrixes indicated by the index entriesin the 'colr' atom.The R, G, and B values in Table 4-4 (page 165) are tristimulus values (such as candelas/meter^2), whoserelationship to CIE XYZ values can be derived from the primaries and white point specified in the table, usingthe method described in SMPTE RP 177-1993. In this instance, the R, G, and B values are normalized to therange [0,1].Table 4-4Index0123–4567–65535Table of primaries, index, and valuesValuesReservedRecommendation ITU-R BT.709-2, SMPTE 274M-1995, and SMPTE 296M-1997 white x =0.3127 y = 0.3290 (CIE III. D65) red x=0.640 y = 0.330 green x = 0.300 y = 0.600 blue x =0.150 y = 0.060Primary values are unknownReservedSMPTE RP 145-1993, SMPTE170M-1994, 293M-1996, 240M-1995, and SMPTE 274M-1995white x = 0.3127 y = 0.3290 (CIE III. D65) red x = 0.64 y = 0.33 green x = 0.29 y = 0.60 bluex = 0.15 y = 0.06ITU-R BT.709-2, SMPTE 274M-1995, and SMPTE 296M-1997 white x = 0.3127 y = 0.3290 (CIEIII. D65) red x = 0.630 y = 0.340 green x = 0.310 y = 0.595 blue x = 0.155 y = 0.070ReservedThe transfer functions listed in Table 4-5 (page 166) are used as shown in Figure 4-2 (page 163).2012-08-14 | © 2004, 2012 Apple Inc. All Rights Reserved.165