What is interactive video?

In a generic sense interactive video is any video in which the user has more than minimal on-off control over what appears on the screen including:

• random access, which allows the user to select and display a segment or an individual frame (picture) with minimal search time
• still frame, which allows any frame to be clearly displayed for as long as the user wishes to view it
• step frame, which enables the user to display the next or previous frame
• slow play which lets the user play the video at any speed up to real-time either forward or backward. (Real-time projection speed is 30 frames per second in North America and Japan and 25 frames per second in most of the rest of the word.)

The videodisc makes this level of control possible. A random-access videodisc contains up to 54,000 numbered frames of analog video and two independent channels of audio. Using the search mechanism of the videodisc player, one can quickly reach any frame. Because the player uses laser technology to read the information, the quality of the image and audio signals is not degraded if the viewer watches one frame for a long time. (Videotape cannot provide truly interactive video, because an individual frame degrades if it is displayed for a long time and because random access is difficult.)

For this type of interactivity to be useful, students and teachers must be able to control the videodisc player easily. At present, three primary methods of control exist:

• Keypads are similar to the remote control for a video-cassette recorder. They allow the user to enter all of the functions described above.
• Bar-code readers allow the user to control the videodisc player by means of information stored in bar codes.
• Computer control delivers all the commands needed for full interactivity through an RS-232 serial port that exists on many videodisc players.                                                            

Adapted from:

”…Interactive Video”                                                                                                                                         

Dean A. Zollman, Kansas State University, Department of Physics,                                                                        

Robert G. Fuller, Department of Physics and Astronomy, University of Nebraska-Lincoln                                   

http://www.phys.ksu.edu/perg/dvi/pt/intvideo.html

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