Analysis of QIM-based audio watermarking using LDPC codes

In this paper, we analyze audio watermarking methods based on quantization index modulation and low-density parity-check (LDPC) codes. We found that dither modulation (DM) can achieve better performance using half-rate Margulis LDPC code even better than some low-rate codes. Then, we propose a scheme based on LDPC codes and DM with distortion-compensation (DC) property which has a robustness benefit of 6 dB versus uncoded case, 2 dB versus algebraic codes, 1 dB versus DM with LDPC code. In DM with DC property, we show that it is possible to achieve. 5 dB better robustness using a scale parameter alpha lower than the theoretically optimal and LDPC codes. Finally our proposal was evaluated against more practical attacks. These results show that our scheme could be a good option for robust watermarks.