Multiple Block-Size Transform Video Coding Using a Subband Structure

The source coding scheme chosen for the experimental research prototype that is currently being designed to demonstrate the digital coding of HDTV for transport within the proposed broadband ISDN (BISDN) fiber optic network is described. The network Interface will be based on a packet based asynchronous transfer mode (ATM) technology, To maximize coding efficiency, run-length coding and variable word length coding are also incorporated in the system. The scheme uses multiple block-size Hadamard transform coding that can be implemented using a set of two-tap filters in a simple subband structure. In spite of the low hardware complexity, which is considered of dominant importance In the overall system performance, high coding efficiency Is obtained. Major features and advantages of this scheme Include the following: 1) Use of a simple, readily integrable basic modular coding block to decompose as well as to reconstruct the signal. 2) Use of the two-tap filler for vertical decomposition results In a structure with minimal line memory requirements. 3) The use of short filters also minimizes response spread In the vicinity of edges which results In excellent rate/distortion coding performance. 4) The resulting image quality has been demonstrated to be quite robust with respect to available bit rate and the structure provides a very flexible means for adjusting the bit rate.