The movie 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 and written when the movie has been initialized with QTMovieOpenForPlaybackAttribute set to YES.
Available in Mac OS X v10.4 and later.
Declaration Syntax Version Information- Available in Monobjc Bridge: 10.6 (For Mac OS X 10.6 and later), 10.5 (For Mac OS X 10.5 and later)