MediaHasCharacteristic(IM: QC)

Inside Macintosh: QuickTime Components /

Chapter 10 - Derived Media Handler Components / Derived Media Handler Components Reference

Functions / General Data Management

MediaHasCharacteristic
The Movie Toolbox calls the MediaHasCharacteristic function with a specified characteristic to allow tracks to be identified by various attributes.
pascal ComponentResult MediaHasCharacteristic 
                                       (ComponentInstance ci,
                                        OSType characteristic,
                                        Boolean *hasIt);
ci
Identifies the Movie Toolbox's connection to your derived media handler.
characteristic
Contains a constant that specifies the attribute of a track. Examples of characteristics that are currently defined are the Movie Toolbox constants VisualMediaCharacteristic and AudioMediaCharacteristic.
hasIt
Contains a pointer to a Boolean value that specifies whether the track has the attribute specified in the characteristic parameter. Set this value to true if the attribute applies to your media handler; otherwise, set this value to false.

DESCRIPTION
The Movie Toolbox might request the search of all tracks with audio data. For example, to find out if a track has a given attribute, the Movie Toolbox queries the media handler for each track by calling MediaHasCharacteristic with a particular constant specified in the characteristic parameter. If your media handler does not recognize a characteristic, return a value of false.
You should implement this function for any media handler that has characteristics in addition to spatial ones. If you have set the handlerHasSpatial capabilities flag, the base media handler automatically handles the VisualMediaCharacteristic constant for you.

RESULT CODES
Any Component Manager result code