Drift-free video coding for privacy protected video scrambling

With video surveillance systems becoming ubiquitous nowadays, protecting people's privacy raises an increasingly serious concern. Video streaming with privacy protection requires modifying parts of the video content. This modification should provide the possibility of unprotected access to the video if the user is authenticated through a private key. However, any modification in the content of a video can result in a drift error and deteriorate the quality of the reconstructed video. In addition, it is required that the privacy protection does not adversely affect the computational complexity and the coding efficiency in terms of bitrate. In this work, we propose a drift-free method for scrambling the privacy protected regions of the frames while preserving the coding efficiency. Our proposed method provides the possibility of utilizing private keys for restricting unauthorized access to the private contents of the video with a small increase in the computational complexity of the encoder and decoder. The experimental results indicate that our proposed drift-free method can achieve a higher coding efficiency of 0.6 dB on average compared to similar methods.