smpte: Check if input caps are the same and create output caps from video info
smpte: Check if input caps are the same and create output caps from video info

This makes sure that also properties like the pixel-aspect-ratio are the same
between both streams and that the output caps contain all fields necessary for
complete video caps.

https://bugzilla.gnome.org/show_bug.cgi?id=735804

ndufresne/gst-plugins-good,wkatsak/gst-plugins-good,jpakkane/gstreamer-plugins-good,ndufresne/gst-plugins-good,surround-io/gst-plugins-good,jpakkane/gstreamer-plugins-good,jpakkane/gstreamer-plugins-good,ndufresne/gst-plugins-good,vatavuserban/gst-plugins-good,vatavuserban/gst-plugins-good,surround-io/gst-plugins-good,ndufresne/gst-plugins-good,surround-io/gst-plugins-good,vatavuserban/gst-plugins-good,wkatsak/gst-plugins-good,jpakkane/gstreamer-plugins-good,vatavuserban/gst-plugins-good,wkatsak/gst-plugins-good,wkatsak/gst-plugins-good,surround-io/gst-plugins-good