Variable length coding of interleaved DCT coefficients for digital HDTV

This paper proposes an algorithm to redcue the bit-rate for transmission of the quantized DCT coefficient data in digital HDTV coders. The variable length coding compresses the quantized DCT coefficient data by removing their statistical redundancy. Zigzag scan is an effective way to improve the performance of the variable length coding. In order to reduce bit-rate further, we propose a new scanning method. Each DCT block is classified into the interleaving group and the non-interleaving group according to the number of non-zero DCT coefficients, and the DCT blocks in the non-interleaving group are encoded using the segmentation and interleaving of DCT coefficients, and the DCT blocks in the non-interleaving group are encoded using only zigzag scan. Simulation results show that the proposed method improves the bit-rate reduction performance by 6.8% when compared with the conventional method.