基于声道低频能量比的MP3压缩域音频水印算法  

Audio watermarking algorithm in MP3 compressed domain based on low frequency energy ratio of channels

作　　者：李晨[1] 王可鑫 田丽华[1] LI Chen, WANG Kexin, TIAN Lihua(School of Software Engineering, Xi＇an Jiaotong University, Xi＇an Shaanxi 710049, Chin)

机构地区：[1]西安交通大学软件学院,西安710049

出　　处：《计算机应用》2018年第8期2301-2305,2352,共6页journal of Computer Applications

基　　金：国家自然科学基金项目(61403302);中央高校基本科研业务费专项资金资助项目(XJJ2016029)~~

摘　　要：为了解决目前大多音频水印算法在应用于MP3音频时存在的效率低下、鲁棒性与不可感知性较难平衡等问题,提出基于MP3帧声道间低频能量的压缩域音频水印算法。该算法的嵌入和提取过程可分别在MP3压缩和解压缩的过程中完成,能大大提高水印的嵌入提取效率。而且由于低频能量具有较好的稳定性,算法利用MP3编解码过程中生成的改进离散余弦变换(MDCT)系数计算得到声道内低频能量,将左右声道内低频能量之比以固定步长量化,最终根据量化结果调整相应的MDCT系数实现水印嵌入;同时,结合不同比例因子频带能量的占比在计算声道内低频能量前对水印嵌入频带进行了筛选,从而能保证水印鲁棒性与不可感知性的平衡。实验显示,该算法可以在维持原始音频可听性的基础上实现对各种类型攻击较好的鲁棒性,尤其是可以抵抗MP3重压缩的攻击。For the inefficiency and imbalance between robustness and imperceptibility of most of the current audio watermarking algorithms when applied to MP3 audio,a watermarking algorithm in compressed domain based on low frequency energy of channels of MP3 frames was proposed. The watermarking can be embedded and extracted during MP3 compression and decompression processes,which greatly enhances the efficiency. Considering the good stability of low frequency energy,the low frequency energy of channels was calculated by using Modified Discrete Cosine Transform（ MDCT） coefficients produced in MP3 encoding and decoding processes,then the ratio between the energy of left and right channels was quantized with fixed step,and the watermarking was embedded by modifying some MDCT coefficients according to quantified results.Meanwhile,with the proportion of energy in different scalefactor bands,the embedding bands were selected before calculating low frequency energy of channels,which ensured a good balance between robustness and imperceptibility. The experimental results show that the proposed algorithm has a good robustness against various types of attacks while maintaining the original audio quality,especially against MP3 recompression attacks.

关 键 词：改进离散余弦变换 音频水印 MP3音频 压缩域 低频能量 

分 类 号：TP391[自动化与计算机技术—计算机应用技术]