Detection of Double MP3 Compression

MPEG-1 Audio Layer 3, more commonly referred to as MP3, is a popular audio format for consumer audio storage and a de facto standard of digital audio compression for the transfer and playback of music on digital audio players. MP3 audio forgery manipulations generally uncompress a MP3 file, tamper with the file in the temporal domain, and then compress the doctored audio file back into MP3 format. If the compression quality of doctored MP3 file is different from the quality of original MP3 file, the doctored MP3 file is said to have undergone double MP3 compression. Although double MP3 compression does not prove a malicious tampering, it is evidence of manipulation and thus may warrant further forensic analysis since, e. g., faked MP3 files can be generated by using double MP3 compression at a higher bit-rate for the second compression to claim a higher quality of the audio files. To detect double MP3 compression, in this paper, we extract the statistical features on the modified discrete cosine transform and apply a support vector machine to the extracted features for classification. Experimental results show that our designed method is highly effective for detecting faked MP3 files. Our study also indicates that the detection performance is closely related to the bit-rate of the first-time MP3 encoding and the bit-rate of the second-time MP3 encoding.