A CELP-Speech Information Hiding Algorithm Based on Vector Quantization

This paper presents a speech information-hiding scheme that is integrated with the CELP (Coded Exited Linear Prediction) speech coding method. The G.729 codec (CS-ACELP) is used to test the efficiency of this scheme. The index-constrained method is applied for the secret information embedding. The selected bits of first-stage and residual vector indices during the Predictive Two-stage Vector Quantization procedure are modulated by the secret information bits. For the imperceptibility of this scheme, the quality of the watermarked speech signal can be controlled by adaptive embedding through referring to the original and watermarked speech. Experimental results show that this scheme can be effective and the distortion of the speech signal is trivial and imperceptible.