Inside Macintosh: QuickTime Components /

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

Functions / Graphics Data Management

MediaGetNextBoundsChange

The MediaGetNextBoundsChange function allows the Movie Toolbox to determine when your media causes a spatial change to the movie.

pascal ComponentResult MediaGetNextBoundsChange 
                                          (ComponentInstance ci,
                                           TimeValue *when);

ci

Identifies the Movie Toolbox's connection to your derived media handler.

when

Contains a pointer to a movie time value. Your media handler must set this time value. Be sure to return a time value in the movie's time base. Use the current effective rate to determine the direction your media is playing. Set this value to -1 if there are no more changes in the specified direction.

DESCRIPTION

The Movie Toolbox uses this function to determine when the next spatial
change will occur in the current movie. Your media handler returns a time
value. Your media handler must examine the edit list of the track that contains
your media in order to derive this duration. You can use the Movie Toolbox's GetTrackNextInterestingTime function to retrieve time values in the movie's time coordinate system. For details on this function and on movie time values, see the chapter "Movie Toolbox" in Inside Macintosh: QuickTime.

Your derived media handler should support this function if you change the shape
of your media's spatial representation during playback.

The Movie Toolbox calls this function only if you have set the handlerHasSpatial flag to 1 in the flags parameter of the MediaSetHandlerCapabilities function.

RESULT CODES

Any Component Manager result code