An intrafield DCT-based HDTV coding for ATM networks

A discrete cosine transform (DCT)-based coding system for 130 Mbps high definition television (HDTV) transmission in asynchronous transfer mode (ATM) networks is described. The system employs low-complexity 8*4 intrafield DCT coding. Major processing stages used by this system include simplified frequency weighting, effective block to linear scans, interblock differential pulse code modulation (DPCM) for DC terms, nonuniform quantization, and two-dimensional entropy coding. Simulations show that the system can achieve high-quality coding at 130 Mbps. A simple rate statistics model is established based on the rates obtained for a group of test pictures. To avoid error propagation due to the use of variable length codes, a packet assembly format is proposed. A two-layer system that segments the coefficients into a main signal and an enhancement signal is employed. The two signals are separately assembled into cells for transmission over the ATM networks with different priorities. Simulation results show that the two-layer DCT system is robust against cell loss.<
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