QuickTime 4 Reference

Introducing a New Registration Mechanism

QuickTime 3 introduces a new movie export component routine that returns the same information that would have been previously stored in the componentManufacturer field of the registered 'spit' components. A new export-specific component flag indicates that the export component implements the new protocol. This enables developers and QuickTime to differentiate between older components and those using the newer mechanism. By implementing the routine, the export component's componentManufacturer field can be used to differentiate components.

The new routine is MovieExportGetSourceMediaType . This routine returns an OSType value through its mediaType parameter, which is interpreted in exactly the same way that the componentManufacturer was previously interpreted. If the export component requires a particular type of track to exist in a movie, it returns that media handler type (e.g., VideoMediaType , SoundMediaType , etc.) through the mediaType argument. If the export component works for an entire movie, it returns 0 through this parameter.



 
EXTERN_API( ComponentResult )

    MovieExportGetSourceMediaType   (MovieExportComponent   ci,

                                 OSType * mediaType);

The following component flag indicates that this routine is implemented:



 
movieExportMustGetSourceMediaType = 1L << 19,

If you implement the MovieExportGetSourceMediaType routine, you must register the component with this flag. Otherwise, the Movie Toolbox will not know to call the routine and will assume the older semantics for the componentManufacturer field.

As in the past, using this mechanism does not replace the need for implementing Validate in your export components. The new mechanism is only used to find candidate components.