Inter-frame distortion drift analysis for reversible data hiding in encrypted H.264/AVC video bitstreams

Due to the privacy-preserving requirement for cloud data management, it is necessary to perform data hiding in the encrypted domain. This paper proposes an effective scheme for reversible data hiding in encrypted H.264/AVC video bitstreams. In the encryption phase, the codewords of intra prediction modes, motion vector differences and partial residual coefficients are encrypted without video bit rate increment for preserving the confidentiality of video content. In the data hiding phase, we first present a theoretical analysis of the picture distortion caused by data embedding and the subsequent inter-frame distortion drift. Based on the analysis, we estimate the embedding distortions caused by modifying different residual coefficients and embed data into residual coefficients with different priorities for decreasing the inter-frame distortion drift. The data embedding is implemented by the histogram shifting technique. If the receiver decrypts the encrypted video bitstream and extracts the embedded data, the original video bitstream can be perfectly recovered. In addition, if the receiver decrypts the encrypted video bitstream without extracting the embedded data, the bitstream can still be decoded to obtain the reconstructed video with good quality. & 2016 Elsevier B.V. All rights reserved.