e set of digital video formats 7.4.5 Video compression that are widely used in current digital video applications. techniques CIF and QCIF support the NTSC and PAL video formats using the same parameters. The SIF format defines Video compression systems are generally comprised of two modes that reduce information redundancy in the spatial and the temporal domains. Spatial compression Table 7.4-2 Digital composite television parameters. and quantization operates on a single image block, making use of the local image characteristics to reduce the bit Description rate. The spatial encoder also includes a variable length coder (VLC) inserted after the quantization stage. The Analog video bandwidth (MHz) VLC stage generates a lossless encoding of the quantized Aspect ratio, hor size/vert size image block. Temporal domain compression makes use of optical flow models (generally in the form of block- Frames per second 29.97 matching motion estimation methods) to identify and Lines per second mitigate temporal redundancy. This section presents an overview of some widely Interlace ratio, fields:frames accepted encoding techniques used in video compression Subcarrier frequency (MHz) systems. Entropy encoders are lossless encoders that are used in the variable length coding (VLC) stage of a video Sampling frequency (MHz) compression system. They are best used for information Samples per active line sources that are memoryless (sources in which each value 114.5 is independently generated), and try to minimize the bit Bit rate (Mbps) 141.9 rate by assigning variable length codes for the input CHAPTER 7.4 Video compression Table 7.4-4 SIF, CIF, and QCIF digital video formats. Description SIF NTSC/PAL Horizontal resolution (Y) pixels 360(352) 180(176) Vertical resolution (Y) pixels 240/288 Horizontal resolution (Cr, Cb) pixels 180(176) 90(88) Vertical resolution (Cr, Cb) pixels 120/144 Bits per pixel (bpp) Interlace fields:frames Frame rate (fps) 30, 15, 10, 7.5 30, 15, 10, 7.5 Aspect ratio hor size/vert size Bit rate (Y) Mbps @