音频压缩中3种整数型MDCT变换的比较  

Comparison of three IntMDCT algorithms in audio compression

作　　者：王膂[1,2] 伍家松[1,3,2] Senhadji Lotfi 舒华忠[1,2] 

机构地区：[1]东南大学影像科学与技术实验室,南京210096 [2]东南大学中法生物医学信息研究中心,南京210096 [3]雷恩第一大学信号与图像处理实验室,法国雷恩35042

出　　处：《东南大学学报（自然科学版）》2012年第2期259-264,共6页Journal of Southeast University：Natural Science Edition

基　　金：国家自然科学基金资助项目(61073138;60873048);国家自然科学基金国际合作与交流资助项目(60911130370)

摘　　要：为了快速计算整数型改进的离散余弦变换(IntMDCT),构造了基于提升变换、模变换以及无穷范数旋转变换的3种计算12点IntMDCT的算法.首先将12点MDCT转化为6点Ⅳ型离散余弦变换(DCT-Ⅳ),并将后者分解为7个Givens旋转变换的乘积;然后分别利用提升变换算法、模变换算法和无穷范数旋转变换算法实现Givens旋转变换的整数型近似计算;最后,对这3种算法在语音信号无损和有损压缩中的运行速度和计算精确度进行比较.实验结果表明,在这3种算法中,基于模变换的IntMDCT算法的运行速度最快;基于无穷范数旋转变换的IntMDCT算法的计算精度最高,并在有损音频压缩中获得的信噪比最高.In order to improve the computation efficiency of the integer modified discrete cosine transform （IntMDCT）, three algorithms based on the lifting scheme, modulo transform and infinity norm rotation transform are formulated respectively for computing the 12-point IntMDCT. First, the12-point IntMDCT is converted into the 6-point type-IV discrete cosine transform （DCT-IV）, which is then factorized into a product of 7 Givens rotation matrices. The integer type Givens rotation ma- trices are approximated by lifting scheme, modulo transform and infinity norm rotation transform,respectively, Finally, the speed and accuracy of these three IntMDCT algorithms are compared in both lossless and lossy audio compression. The experimental results show that in the three algo- rithms, the IntMDCT algorithm based on the modulo transform has the highest computation speed. The IntMDCT algorithm based on the infinity norm rotation transform has the highest accuracy, and can achieve the highest signal to noise ratio （SNR） in lossy audio compression.

关 键 词：提升算法 模变换 无穷范数旋转变换 整数型MDCT 音频压缩 

分 类 号：TP391[自动化与计算机技术—计算机应用技术]