QVideoWidget has an enumeration: AspectRatio: http://doc.trolltech.com/4.7-snapshot/qvideowidget.html#AspectRatioMode-enum
Qt already has such an enum: http://doc.trolltech.com/4.6/qt.html#AspectRatioMode-enum

I see that the enumeration from Qt has one more value and that QVideoWidget would need to be improved to support that additional enum value this does not justify duplicating an enum. Note that the video player on the iphone support both of these aspect ratio modes: You can switch between them using double tap.

This issue has already been reported here:
http://discussion.forum.nokia.com/forum/showthread.php?t=192159