Privacy region protection for H.264/AVC by encrypting the intra prediction modes without drift error in I frames

While video surveillance systems have become ubiquitous in our daily life, this has also brought some serious privacy concerns. Therefore, recent research in this area has included a focus on privacy region protection. Existing video scrambling techniques are being applied to specific regions of interest in a video while the background is left unchanged. In this paper, a new method involving the encryption of intra prediction modes (IPM) is proposed for privacy region protection without drift error in I frames. Compared with a previous technique that uses encryption of IPM, the proposed method offers savings in the bitrate overhead. To enhance the scrambling effect for the privacy region, the proposed method can support the combination of IPM with encryption of the sign bits of nonzero quantized transform coefficients in the privacy region. Experimental results and analysis based on H.264/AVC were carried out and verify the effectiveness of the proposed method.