Digital HDTV Compression Techniques for Terrestrial Broadcasting

Abstract

The latest digital signal processing and VLSI developments have significantly contributed the rapid emergence of digital image compression techniques in HDTV applications. Significant progress has been occurring in the development of advanced television techniques for terrestrial broadcasting. Currently, the most promising advanced television systems in the United States explore the possibility of a digital signal fitting into a 6 MHz terrestrial broadcast channel. One of the challenges of designing a digital system is to compress an HDTV source so as to transmit it in a 6 MHz television channel. The fundamental goal of digital HDTV compression is to reduce the bit rate while maintaining an acceptable image quality. Numerous bandwidth compression techniques have been developed, such as differential pulse code modulation (DPCM), subband coding including transform coding, vector quantization, hybrid coding, entropy coding and adaptive versions of these techniques in response to the growth of image-processing methods. These techniques usually explore the psychophysical as well as statistical redundancies in the image data to reduce the bit rate. This paper will review these compression techniques, such as intraframe coding, interframe coding, motion prediction/compensation, subband/transform coding, quantization, entropy coding and buffer. Also, it will discuss how these techniques are employed in the proposed digital HDTV terrestrial broadcasting systems. To compare the proposed digital systems, a table of attributes, characteristics and processes of digital HDTV terrestrial broadcasting systems is provied.