videotestsrc is just an element, not a bin container, so we must use round brackets to embrace the elements all, which means rtsp://127.0.0.1:8554/test is the default mount point.
1 2 | test-launch.exe "( videotestsrc ! qsvh264enc ! rtph264pay name=pay0 pt=96 )" gst-launch-1.0.exe playbin uri=rtsp://127.0.0.1:8554/test --gst-debug=d3d11window:5 |