MPEG-1 Layer III 音訊編解碼演算法最佳化及DSP晶片實現

Abstract

這篇論文提出一套MP3編解碼的最佳化演算法及有效的16位元定點DSP實現。在MP3編碼最佳化中，我們基於移除計算量龐大的聲響心裡模型，提出一套新的速率控制迴圈演算法，並採用頻寬控制及動態位元分配等。在MP3解碼最佳化中，我們提出一套新的解量化方程式實現法，並可適用在定點處理器中；在實現IMDCT和子頻帶合成上，也採用了快速演算法。我們將MP3編解碼最佳化的演算法實現在一顆16位元定點DSP，ADSP-2181上，並採用動態定點格式降低定點運算時的失真。實現後的MP3編碼器僅需21.05 MIPS及44千位元組記憶體，而解碼器僅需18.67 MIPS及44.3千位元組記憶體，相較於其他商業化產品及學術研究，能提供最好的效能。最後，本篇論文還提出一個基於32位元RISC及DSP的雙核心嵌入式系統整合設計。

This thesis presents the algorithm optimization and efficient 16-bit fixed point DSP implementation of MP3 encoding and decoding algorithms. In the MP3 encoding algorithm, we propose several approaches including the removal of psychoacoustic model, simplified iteration loop, fast rate control loop and applying of bandwidth control and dynamic bit allocation proportional to the energy of granules. In the MP3 decoding algorithm, we propose a fast dequantization method with high SNR in fixed point implementation and apply fast algorithms in IMDCT and subband synthesis. The algorithms are also completely realized on a 16-bit fixed point DSP, ADSP-2181, and the dynamic fixed point format is applied to improve audio quality. The MP3 encoder consumes 21.05 MIPS and 44k bytes memory, and the MP3 decoder consumes 18.67 MIPS and 44.3k bytes memory. Both have superior performance than other commercial products and paper works. Finally, this thesis also presents an integrated design of a dual core embedded system with a 32-bit RISC, Intel□ StrongARM SA-1110, and ADSP-2181 DSP.