Adaptive data hiding in compressed video domain

In this paper we propose a new adaptive block based compressed domain data hiding scheme which can embed relatively large number of secret bits without significant perceptual distortion in video domain. Macro blocks are selected for embedding on the basis of low inter frame velocity. From this subset, the blocks with high prediction error are selected for embedding. The embedding is done by modifying the quantized DCT AC coefficients in the compressed domain. The number of coefficients (both zero and non zero) used in embedding is adaptively determined using relative strength of the prediction error block. Experimental results show that this blind scheme can embed a relatively large number of bits without degrading significant video quality with respect to Human Visual System (HVS).