Design of a novel synthesis filter for real-time MPEG-2 audio decoder implementation on a DSP chip

This paper describes the design of a novel synthesis filter-for real-time i mplementation of MPEG-2 audio decoder on a single, programmable DSP chip. I n the first phase of our design we propose a fast subband synthesis filter bank employing a decomposed IDCT block with reduced multiplication stages, shared by both MPEG-1 and MPEG-2 decoders. In the second phase of the desig n, a parameter analyzer block is adopted to take advantage of the multichan nel computing structure in MPEG-2 thereby further reducing the number of MA C operations. In the final phase, we propose a low-cost decoder employing u northodox methods of boosting performance by gracefully degrading quality o f service. The overall runtime of the decoder has been reduced by 60% when compared to the modified ISO decoder employing a synthesis filter bank with fast IDCT block. Real-time performance validations have been made by re-tuning time-c ritical code sections for both native VLIW and DSP architectures. The final implementation successfully passes all ISO/IEC MPEG-2 audio compliance tes ts and achieves near-transparent audio decoding and signal reconstruction o n the fly.