 for understanding the in- Description PAL/SECAM ternational video compression standards developed by the International Telecommunications Union (ITU) and Luminance channel the International Standards Organization (ISO). These Analog video bandwidth (MHz) standards contain specific recommendations for use of the digital video formats described here. Sampling frequency (MHz) Composite television digital video formats are used Samples per active line for the digital broadcasting, SMPTE digital recording, and conversion of television broadcasting formats. Table Bit rate (Mbps) 7.4-2 contains both analog and digital system parameters Two color difference channels for the National Television Systems Committee (NTSC), Analog video bandwidth (MHz) and Phase Alternating Lines (PAL) composite broadcast formats. Sampling frequency (MHz) Component television signal digital video formats have been defined by the International Consultative Samples per active line Committee for Radio (CCIR) Recommendation 601. It is Bit rate (Mbps) based on component video with one luminance (Y) and two color difference signals (Cr and Cb). The raw bit rate for the CCIR 601 format is 162 Mbps. Table 7.4-3 contains important systems parameters of the CCIR different vertical resolution values for NTSC and PAL. 601 digital video studio component recommendation for The CIF and QCIF formats also support the H.261 both NTSC and PAL/SECAM (sequentiel couleur avec modified parameters. The modified parameters are memoire). integer multiples of 8 in order to support the 8 X 8 pixel The ITU Specialist Group (SGXV) has recom- two-dimensional DCT operation. Table 7.4-4 lists this mended three formats that are used in the ITU H.261, set of digital video standard formats. The modified H.263, and ISO MPEG video compression standards. H.261 parameters are listed in parenthesis. They are the standard input format (SIF), common interchange format (CIF), and the low bit rate version of CIF called quarter CIF (QCIF). Together, these formats describe a comprehensiv