Playback Characteristics

While Ultimotion is a playback-time scalable-video data stream, the magnitude that the data stream will "scale" is determined by the amount of information that is encoded in the data stream when it was created; that is, the amount of data placed in the data stream at creation time determines the "maximum" playback characteristics that a particular stream can achieve. In turn, the processing capabilities of the playback system determine how much of the data can be processed and presented during playback. Therefore, the playback characteristics of a given video are a function of the data put into the video by the author and the processing capabilities of the playback system.

The factors affecting the data stream at creation time are:

Resolution

Width and height of video
Frame duration
Frequency at which frames are to be created
I-frame rate
Frequency at which reference frames are to occur
Data rate
Average amount of data allowed for a second of video

Factors affecting the playback of a video are:

• Processing power of the CPU 
  Throughput of data storage (for example, CD-ROM, hard disk, LAN)
  
  Efficiency of the display subsystem (such as the video adapter and display driver)

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