ROI encryption for the HEVC coded video contents

In this paper we investigate privacy protection for the HEVC standard based on the tile concept. Tiles in HEVC enable the video to be split into independent rectangular regions. Two solutions are proposed to encrypt the tiles containing the Region Of Interest (ROI). The first solution performs encryption at the bitstream level by encrypting all HEVC syntax elements within the ROI tiles. The second solution enables a selective encryption of the ROI tiles under constant bitrate and format compliant requirements. To avoid temporal propagation of the encryption outside the ROI boundaries caused by inter prediction, the motion vectors of non ROI regions are restricted inside the non encrypted tiles in the reference frames. Simulation results show that the proposed solutions perform secure and adaptive encryption of ROI in the HEVC video. Moreover, the bitrate overhead caused by the MVs restriction window varies between 1%-2.5% depending on both the video content and the number of tiles within the frame.