2009 Volume E92.A Issue 12 Pages 3248-3257
An entropy decoding engine plays an important role in modern multimedia decoders. Previous researches that focused on the decoding performance paid a considerable attention to only one parameter such as the data parsing speed, but they did not consider the performance caused by a table configuration time and memory size. In this paper, we developed a novel method of entropy decoding based on the two step group matching scheme. Our approach achieves the high performance on both data parsing speed and configuration time with small memory needed. We also deployed our decoding scheme to implement an entropy decoding processor, which performs operations based on normal processor instructions and VLD instructions for decoding variable length codes. Several extended VLD instructions are prepared to increase the bitstream parsing process in modern multimedia applications. This processor provides a solution with software flexibility and hardware high speed for stand-alone entropy decoding engines. The VLSI hardware is designed by the Language for Instruction Set Architecture (LISA) with 23Kgates and 110MHz maximum clock frequency under TSMC 0.18µm technology. The experimental simulations revealed that proposed processor achieves the higher performance and suitable for many practical applications such as MPEG-2, MPEG-4, H.264/AVC and AAC.
