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Image, Audio, and Video Extenders Administration and Programming


What is a video scene change?

Imagine a television studio that records programs on video tape for subsequent telecast. Recently the studio has started using the Video Extender to store clips of its video tapes in a DB2 database. This gives studio personnel the opportunity to query traditional types of information about their programs as well as view clips of the programs.

The studio would like the option of previewing a video clip. They want the ability to view a visual summary, called a storyboard. An example of a storyboard is shown in Figure 22. Viewing storyboards can help studio employees get the gist of a video without having to view the entire video. It can also help employees decide if a video is the right video for their needs (for example, whether it merits downloading and viewing). This requirement is very important to the studio. Viewing a storyboard instead of an entire video can reduce download and viewing time dramatically. For more information on using video scene change detection capabilities in this way, see Storing information about all the shots in a video.

Figure 22. A video storyboard


REQTEXT

The studio is planning to use the video scene change detection capabilities of the Video Extender to capture representative frames for their storyboards.

A video scene change is a point in a video

clip where there is a significant difference between two successive frames. This happens, for example, when the camera recording a video changes its point of view. The frames between two scene changes constitute a shot.

When the Video Extender detects a scene change6, it records data for the associated shot. The data includes the number of the frame that begins the shot, the number of the frame that ends the shot, and the number of a representative frame within the shot. The shot data also includes the pixel content of the representative frame.


Footnotes:

6
The video scene change detection code includes the University of California at Berkeley MPEG decoder, with modifications from the Boston University Multimedia Communication Laboratory.


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