The preferred volume; the value for this key is of type NSNumber, interpreted as a float.

This attribute can be read and written. This attribute can be read but not written when the movie has been initialized with QTMovieOpenForPlaybackAttribute set to YES.

The preferred settings refer to settings contained in the movie file (or movie data) itself. The actual settings refer to the actual values of those settings. For instance, a movie can have a preferred rate of 2, and a good movie playing application will respect that setting. But an application or the user can set the actual rate to some other value. The non-preferred settings can change dynamically, but the preferred settings will not.

Available in Mac OS X v10.4 and later.