QuickTime 4 Reference

Introduction to QuickTime Video Effects

QuickTime video effects are implemented as components , which are the standard mechanism used to extend QuickTime. Effect components are actually a specialized type of image decompressor component. For more information about implementing image decompressor components, see Chapter 4, "Image Compressor Components."

To use an effect component in a QuickTime movie, you add an effect track to the movie. The size and duration of the track determines the area of the movie that is affected and how long the effect runs.

The effect track has two important attributes: the effect description and the input map. The effect description is a sample, added to the media of the effects track, that selects which effect to use and contains the parameters for that effect. The input map describes the sources that the effect works on. Effect components use whole tracks as sources. A track reference redirects the output of the source track to the effect track. You may need to make new tracks, referencing parts of existing video tracks, to act as sources for your effects.

Once you have arranged your source tracks and added the effects track to your movie, QuickTime automatically executes the effect when the movie plays. QuickTime generates as many frames per second as possible for the effect, so the effect will run as smoothly as the CPU and display hardware of the target machine permit.

You can also use the QuickTime video effects outside the context of a QuickTime movie. You still supply an effect description, but instead of creating an effect track, you write code that executes the individual steps of the effect. For details, see the section "Using Video Effects Outside a QuickTime Movie" .