Inside Macintosh: QuickTime /

Chapter 2 - Movie Toolbox / Movie Toolbox Reference

Media Functions / Selecting Media Handlers

GetMediaDataHandlerDescription

The GetMediaDataHandlerDescription function allows your application to retrieve information about a media's data handler. You specify the media.

pascal void GetMediaDataHandlerDescription (Media theMedia, 
                                 short index, OSType *dhType, 
                                 Str255 creatorName, 
                                 OSType *creatorManufacturer);

theMedia

Specifies the media for this operation. Your application obtains this media identifier from such Movie Toolbox functions as NewTrackMedia and GetTrackMedia (described on page 2-138 and page 2-190, respectively).

index

Identifies the data reference. You provide the index value that corresponds to the data reference for which you want to retrieve the data handler description. You must set this parameter to 1.

dhType

Contains a pointer to a field of data type OSType. The Movie Toolbox returns the data handler type identifier. This value indicates the type of data reference supported by this data handler. This value also corresponds to the component subtype specified for the data handler component. All QuickTime data references have a type value of 'alis'. If you do not want to receive this information, set the dhType parameter to nil.

creatorName

Points to a string. The Movie Toolbox returns the name of the data handler's creator. If you do not want to receive this information, set this parameter to nil.

creatorManufacturer

Contains a pointer to a long integer. The Movie Toolbox returns the 4-byte value that identifies the manufacturer of the component. If you do not want to retrieve this information, set this parameter to nil.

DESCRIPTION

The Movie Toolbox returns information about that media's data handler. This information describes the data handler that created the media data, not the handler that is currently assigned to the media.

ERROR CODES

invalidMedia

-2008

This media is corrupted or invalid