QuickTime 4 Reference

Registering Movie Data Export Components

Before QuickTime 3, it was not possible to have more than one export ('spit' ) component registered for the same type of file and the same track media type. Additionally, it was not possible to have more than one component that exports to a type of file that takes data from the whole movie. What this meant was that if two separate exporters wanted to export to the 'PICT' file format, for example, only one could be registered at a time.

In the past, the distinction between a media type-specific (or track type-specific) exporter and a movie-wide exporter was based on the componentManufacturer value with which the component was registered. Media type-specific components stored the type of the media handler ('mhlr' ) component in this field. Movie-wide components used 0 in this field.

QuickTime 3 and later versions allow more than one export ('spit' ) component to be registered for the same type of file and the same export source (the movie or the particular track type). This is accomplished in a way that preserves compatibility with third-party components that may have already been written using the former rules.

Introducing a New Registration Mechanism

Changes to QuickTime 3 Export Components