* https://stackoverflow.com/questions/59858898/how-to-convert-a-video-on-disk-to-a-rtsp-stream
* http://gstreamer-devel.966125.n4.nabble.com/RTSP-Server-from-a-manually-created-and-linked-pipeline-td4680305.html
* http://gstreamer-devel.966125.n4.nabble.com/Using-C-API-based-pipelines-in-RTSP-server-without-quot-launch-quot-arg-td4680144.html
+* RTSP on_media_configure and appsrc: https://github.com/GStreamer/gst-rtsp-server/blob/master/examples/test-appsrc.c
+* Link two pipelines: http://gstreamer-devel.966125.n4.nabble.com/Two-pipelines-link-them-merge-them-easy-handling-td4686753.html
a "relay" between cameras and rtsp, in rust: