Few weeks agio I posted my notes about picture-in-picture compositing in Gstreamer using nothing else than the gst-launch command line tool. I also wrote that I could not figure out how to use the xpos, ypos, zorder properties of the GstVideoMixerPad element. I got a comment on this note from Jan Schmidt telling that these properties can not be used with gst-launch but are easily accessible from Python. He also gave a very cool example that shows how to use it.
In a previous post I gave a few examples showing how simple text overlays can be added to any video stream in GStreamer. Now it’s time to look at compositing between two or more video streams, also called picture in picture. As you’ll see it is still very easy to achieve even when using nothing more than the gst-launch command line tool. First we look at some basic examples, then we finish with a more complex “Live from Pluto” video wall.