Compression history identification for digital audio signal
Compression history identification plays a very important role in digital multimedia forensics. However, most existing literatures mainly focus on digital image forensics, and just a few works consider digital audio. In this paper, we investigate two popular compression schemes in digital audio, that is, MP3 and WMA, and try to reveal the compression history for a questionable audio signal in the original uncompressed WAV format via analyzing some statistical characteristics of the modified discrete cosine transform coefficients of the audio. The extensive experimental results have shown that the proposed method can effectively identify whether the given audio has been previously compressed with MP3 and/or WMA, and can further estimate the hidden compression rates, even the compression rate is as high as 128 K bps (bits per second).