The 'mirrored' property indicates the QVideoFrames need to be mirrored along their vertical axis. This is typically needed for video frames coming from a front camera on a mobile device. This is implemented as a string-based property. In Qt 5.6, this should be replaced by a new public function. Change-Id: Ideb7de81e83f66826f4efb5f2951c4beec13546b Reviewed-by: Christian Stromme <christian.stromme@theqtcompany.com>