Research On H.264 Video Information Hiding Based On Interframe Coding

With the rapid development of communication technology and Internet,digital multimedia has become an irreplaceable role in daily life,work and industry.The popularity of multimedia applications leads to copyright and information security issues which are becoming increasingly serious.Information hiding based on multimedia provides an effective solution to the problems of information security.The digital video is not only rich in content,but also contains lots of data,which provide many embeddable positions for information hiding.Video is an ideal carrier for information hiding.As one of the widely used and studied video codec standards,H.264/AVC provides a reliable carrier framework for the study of video information hiding due to its excellent coding performance and unique hierarchical structure.Motion vectors are obtained by motion estimation and motion compensation in H.264 video codec.Because of the large number of motion vectors and the small impact on visual quality after modifications,there is a lot of research of information hiding based on motion vectors.Based on H.264/AVC video information hiding,this paper will be unfolded according to the following two parts:1)A video information hiding scheme based on the similarity of macroblocks for motion vectors is proposed.In inter-frame prediction modes,the motion vectors obtained from motion estimation and motion compensation are used as embedding locations of secret information.The concept of macroblock similarity is introduced to measure the fidelity of the carrier in terms of the local optimality and adjacent correlation of motion vectors.The motion vectors in the macroblock with the greatest similarity are selected as the embedding locations to prevent the distortion caused by the modification of the video.At the same time,the vector expansion coding is designed,which can adjust the size and direction of the modification adaptively according to the trend of the motion vector,so as to ensure that the modified motion vector will not have too large mutation and further reduce the distortion.The experimental results show that the scheme not only has a large hiding capacity,but also can guarantee the video quality and achieve the goal of reducing distortion.2)A video information hiding scheme based on additive motion vector pairs is proposed.Considering that the modification of a single motion vector will change the optimality of adjacent motion vectors,this scheme regards two adjacent motion vectors as a set of motion vectors pairs and adds them together to get a new joint vector,which is defined as an additive motion vector pair.At the same time,the two motion vectors in a set of additive motion vectors are modified simultaneously to realize the modification of their combined vectors,so that the secret information can be embedded in the phase angle of the combined vectors.Finally,according to the vectors offset,the threshold of the combined vectors offset is set to determine the embedding location,so that the secret information can be hidden.The experimental results show that the scheme not only has good video quality,but also has large hiding capacity.