video compression and vlsi

Why video compression has become the dominant video processing application of TV? An analog TV channel only needs a 5 MHz analog channel for the transmission, conversely in case of digital video with: 8 bit A/D, 720 pixels for 576 lines (54 MHz sampling rate) we need a transmission channel with a capacity of 168.8 Mbit/s!!! In case of digital HDTV the capacity for: 10 bit A/D, 1920 pixels 1152 lines raise up to1.1 Gbit/s!!! No affordable applications, in terms of cost, are thus possible without video compression.
These reasons have raised also the need of worldwide standards for video compression so as to achieve interoperability and compatibility among devices and operators. H.261 is the names given to the first digital video compression standard specifically designed for videoconference applications, MPEG-1 is the name for the one designed for CD storage (up to 1.5 Mbit/s) applications, MPEG-2 for digital TV and HDTV respectively from 4 up to 9 Mb/s for TV, or up to 20 Mb/s for HDTV; H.263 for videoconferencing at very low bit rates (16 – 128 kb/s). All these standards can be better considered as a family of standards sharing quite similar processing algorithms and features.