On the Channel Characteristic of Dither Modulation Data Hiding for MP3 Compression

In this paper, we focus on the channel characteristics of audio files when MPEG 1 layer III (MP3) compression is applied. We propose a data hiding scheme which achieves 61.25 bits per second, around 39 bits of benefit than Cvejic which uses turbo codes. Our scheme embeds binary data on specific sub-bands in wavelet domain using dither modulation. Those specific sub-bands were found to be more robust against compression. To achieve better payload, low-density parity-check (LDPC) codes are used. The advantage of this scheme relies on obtaining more reliable log-likelihood ratio (LLR) using a multi-channel configuration which provides different channel information according to each wavelet sub-band. The embedded information does not introduce audible distortion, the audio´s quality is SNR higher than 30 dB for all tested audio files.