The software MD-shots , for "Motion-based Detection of shots" performs the temporal segmentation of a video into shots. It is developed in languages C-ANSI and C++. Prior to any content-based video indexing, it is necessary to build a structured temporal representation of a video into elementary shots. This implies to detect "cuts" and progressive transitions corresponding to shot changes. By progressive transitions, we mean special effects, such as fade-in, fade-out, dissolve, wipe, ...
The proposed method to achieve the video partitioning in elementary shots [1] exploits the temporal coherence, within a same shot, of an appropriate information related to the global dominant motion between two successive images (Fig. 1). The later, represented by a 2D parametric model, is estimated using the Motion-2D [2] software. We consider in fact the temporal evolution of the normalized size of the support associated to the estimated dominant motion. At the time of a "cut", no motion model can correctly describe the transformation between the two succesive images, which leads to a sudden fall of the support size value. At the time of progressive transitions, this fall is less prononced but occurs over a time interval This detection of jumps is carried out by a statistical Hinkley test, whose implementation is simple and efficient. An original asset of the method is to handle the detection of the various kinds of transitions involving only one parameter to be set by the user. Moreover, a same value of this parameter is used for the two types of treated transitions.
To act on the processing rate used, it is possible to specify the first
and the last levels considered in the image pyramids. It is also possible
to retain a temporal under sampling of the sequence to be processed. According
to options selected, we can currently reaches processing rates ranging
from 0,6 Hz to 2,6 Hz on a SUN Ultra-Creator station at 300 MHz. This software
was transferred to Alcatel-CRC
and to Ina. In addition, a licence agreement
of commercial exploitation was concluded with the company Arts
Video Interactive (insertion in the commercial product marketed MOVIDEO-2
STUDIO).
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