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CEC: Cluster Embedding Coding for H.264 Steganography

In this letter, we first propose a novel coding method to design content-adaptive H.264 steganography with quantized discrete cosine transform (QDCT) coefficients. Currently, the state-of-the-art steganographic methods minimize a heuristically defined distortion function using STCs and embed messages in a pixel-wise manner. When this concept is directly applied to H.264 steganographic designing, there are two factors that hinder the improvement of empirical security: interaction of embedding changes, and the block-wise characteristics of video compression. Our proposed CEC scheme performs both message embedding and video compression in the block-wise manner where a cluster of elements in a cover block are modified simultaneously, and defines a joint distortion function on the cover block to reflect the features of rate-distortion optimization. Experimental results demonstrate the effectiveness of our proposed coding method.