Information hiding algorithm for H.264 based on the motion estimation of quarter-pixel

A scheme of information hiding for H.264 based on motion estimation of 1/4 pixel is proposed in this paper. Information is embedded by modulating the best search point of each sub-block during the step of motion estimation of 1/4 pixel. The modulation is based on the mapping rules between these points and the hidden bits. By introducing the rate-distortion cost during the process of modulating, the proposed scheme achieved a better balance of rate-distortion, meanwhile, it had a smaller influence on the quality of video and the bit-rate of video. This scheme could detect the secret information rapidly, which meets the requirement of the real-time processing of video. Experimental results also demonstrate that it is a extremely effective scheme.