add: g_return_if_fail (GST_IS_VIDEO_WIDGET(bvw->priv->vw));  gst_video_widget_set_scale (bvw->priv->vw, ratio);
context: bacon_video_widget_set_scale_ratio (BaconVideoWidget *bvw, gfloat ratio){	g_return_if_fail (bvw != NULL);	g_return_if_fail (BACON_IS_VIDEO_WIDGET(bvw));	g_return_if_fail (GST_IS_PLAY(bvw->priv->play));}