The expert needs to find a particular segment in the video to discuss it with the person seeking help. Later, the person may want to ask the expert another question which would require showing the expert some material the person is looking at in the video or courseware. Few systems support this degree of dynamic interaction. Continuous Media Toolkit 3. Desktop Video Conferencing System 5.
Devices represent the audio and video hardware that can be used by an application.
Resources represent application independent, but media specific continuous media abstractions built on devices. Examples are live cameras that can be used to capture a motion JPEG stream, Windows that can display an MPEG video stream, microphones that can be used to capture CD quality stereo audio streams, and speakers that can play 16-bit linear audio data. Another example of a resource is a clipfile that stores a sequence of blocks or frames of a particular type of media. A script is a file that specifies how clips from different clipfiles are organized into synchronized streams. Sources and destinations are application-specific abstractions that connect resources.