1. INTRODUCTION
Television (TV) has been playing a very important role in our life since its invention. TV industry has been significantly improved due to the recent advances in electronics and telecommunication sectors. Digital technology is the latest step in the evolution of TV. More dramatically than the transition from black and white to color; digital TV will change the way we view the TV. One of the key features of digital TV is high definition television (HDTV). HDTV is a wide-screen format that offers a 100% improvement in the picture resolution of the analogue systems currently use. HDTV will provide high quality, crystal clear picture similar to a movie theater screen, CD quality sound and perfect reception. Other than that HDTV also provide many more features. Since HDTV provides a very high resolution pictures compared to the analogue TV, it needs more than 1 Gbits/s data rate. However due to the bandwidth and interference constraints, the maximum data rate is limited to 20 Mbits/s over the terrestrial channel. Therefore video signal must be compressed before the transmission. This compression can be done by properly exploiting the spatial and temporal correlations of the image sequence and also by considering the properties of the human visual system. Several compression algorithms have been proposed [1]–[3]. However, in the Grand Alliance System [4], video compression is accomplished in accordance with MPEG-2 video coding standard.