Increase of embedding capacity of the H.264/AVC data hiding based on the intra-prediction modes
Data hiding methods applied to the newest video codec H.264/AVC are exploiting several modules of this codec such as the discrete cosine transform (DCT) coefficients and the intra prediction modes. The objective is to realize a good compromise between the embedding capacity, the increase in bitrate and the video quality, to satisfy several applications such as authentication or covert communication. In this paper we present a new approach to exploit the intra prediction modes for data hiding of the 4x4 luminance blocks. The objective is to ensure a good data embedding capacity and to preserve the encoding and the decoding times to satisfy reel time applications. The proposed method is based on dividing the intra prediction modes into four groups. Each group in composed of modes that have close prediction directions. Embedding the secret data is based on applying modification between modes of the same group in order to maintain visual quality and limit the number of additional calculation procedures. The increase of embedding capacity relies on the group composed on four modes since it allows the embedding of two bits per mode instead of one.
Data hiding, H.264/AVC, Intra prediction modes, Embedding capacity, Covert communication