Detection of Motion-Incoherent Components in Video Streams

Motion coherency has recently been identified as a desirable property for watermarks embedded within video streams in order to withstand temporal frame averaging along the motion axis. Nevertheless, no tool has been proposed to easily evaluate the motion coherency of a given watermarking system. Today, this assessment relies on a computationally expensive procedure, namely, (1) embed a watermark, (2) perform temporal frame averaging, and (3) check for the presence of the watermark. In this article, a novel oracle is designed to detect whether a video stream contains any motion-incoherent component or not. Since such incoherence can be introduced by nonmotion-coherent watermarking algorithms, this tool has proven to be most valuable to distinguish watermarked from nonwatermarked content. The oracle relies on some features extracted from error frames after motion compensation. Experimental results demonstrate the efficiency of the proposed method with uncompressed and compressed video streams.