The flexibility of the digital medium, shown by its ability to integrate text, audio, and video, permits many new methods of obtaining and manipulating information. The large amount of data required to represent an image sequence restricted research into digital video until recent years. Conventional compression techniques, although making digital video possible, do not utilize the semantic content of the image sequence. Facsimile encodes the text using a statistical model of the text image. Synthetic movies attempt to separate the semantic content of a sequence from the description of the objects in the scene, allowing separate transmittal of the two components.
Synthetic movies are motion image sequences that are constructed as they are being viewed.
They are composed at the receiver, usually under the interactive control of the user. The content of the components and the complexity of the reconstruction vary. Examples of synthetic movies range from videodisc training tools, to simple molecular modeling tools, interactive flight simulators and video games. Synthetic movies may be categorized by the type of synthesis allowed. Intraframe synthesis permits the actual content of the images being displayed to be manipulated, whereas interframe synthesis is restricted to controlling the temporal evolution of the sequence.