General Data Management
While the base media handler isolates your component from the details of media data access, your derived media handler still needs to keep track of certain information in order to support movie playback and creation. This section discusses functions that help your media handler manage its information.Your media handler may store proprietary information in its media. The Movie Toolbox calls two media handler functions in order to give you an opportunity to retrieve or store this information. The
MediaPutMediaInfofunction allows you to store your special information in your media. TheMediaGetMediaInfofunction delivers that data to your media handler.The Movie Toolbox tells your media handler when its track has been enabled or disabled by calling your
MediaSetActivefunction. The Movie Toolbox prepares your handler for playback by calling yourMediaPrerollfunction. Whenever your media's playback rate changes, the Movie Toolbox calls yourMediaSetRatefunction. Whenever the track that uses your media is edited, the Movie Toolbox calls yourMediaTrackEditedfunction.If the Movie Toolbox has called its
SetMediaSampleDescriptionfunction on a sample description, it uses theMediaSampleDescriptionChangedfunction to notify your media handler of the change.The Movie Toolbox allows tracks to be identified by various characteristics. For instance, it is possible to request that all tracks containing audio information be searched. To determine whether a track has a given characteristic, the Movie Toolbox queries the media handler for each track. The Movie Toolbox calls the
MediaHasCharacteristicfunction with the specified characteristic.The Movie Toolbox uses two functions to inform you about changes to your media's time environment. The
MediaSetMediaTimeScalefunction allows the Movie Toolbox to change your media's time scale. TheMediaSetMovieTimeScalefunction allows the Movie Toolbox to tell you when the movie's time scale has changed.
Subtopics
- MediaPutMediaInfo
- MediaGetMediaInfo
- MediaSetActive
- MediaPreroll
- MediaSetRate
- MediaTrackEdited
- MediaSampleDescriptionChanged
- MediaHasCharacteristic
- MediaSetMediaTimeScale
- MediaSetMovieTimeScale