Não foi possível transmitir o RTSP usando o GStreamer

Estou tentando transmitir vídeo RTSP usando o GStreamer. Eu estou usando o test-launchexemplo de gst-rtsp-server.

Servidor:

./test-launch "(videotestsrc ! x264enc ! h264parse ! rtph264pay)"

Cliente: VLC.

Quando tento abrir o URI rtsp://0.0.0.0:8554/testno VLC, recebo um erro:

live555 debug: we will now try HTTP tunneling mode
live555 debug: connection error -115
live555 error: Failed to connect with rtsp://127.0.0.1:8554/test
core debug: no access_demux modules matched
core debug: creating access 'rtsp' location='127.0.0.1:8554/test', path='(null)'
core debug: looking for access module matching "rtsp": 25 candidates
core debug: net: connecting to 127.0.0.1 port 8554
core debug: connection succeeded (socket = 28)
access_realrtsp debug: rtsp connected
access_realrtsp warning: only real/helix rtsp servers supported for now
core debug: no access modules matched
core error: open of `rtsp://127.0.0.1:8554/test' failed

Eu tentei testá-lo com o wget e obter erro 503: Service Unavailable

log do gstreamer:

0:00:10.219925652  2772       0xcb4ca0 ERROR             rtspclient rtsp-client.c:767:find_media: client 0xe140c0: can't prepare media
0:00:10.220158204  2772       0xcb4ca0 ERROR             rtspclient rtsp-client.c:2283:handle_describe_request: client 0xe140c0: no media

O que estou fazendo errado?