During the intra prediction step of H.264/AVC video compression standard

information hiding is implemented by modifying the intra prediction modes of qualified intra 4×4 luma blocks.The modulation is based on the mapping rules between these modes and the hidden bits.The specific positions of the host 4×4 blocks are determined by the features of every block and a position template indicated by the key.The detection of hidden information needs no original media

and merely requires decoding the intra prediction modes from bit stream rather than decoding the whole video.