rtpbin receiver doesn't output X-GST encoded streams - gstreamer

Question

I'm trying to make a server and client application that sends and receives a raw video stream using rtpbin. In order to send an uncompressed videostream I'm using rtpgstpay and rtpgstdepay to payload to the data.
The server application can succesfully send the video stream with the following pipeline:
gst-launch-1.0 -vvv rtpbin name=rtpbin \
videotestsrc ! \
rtpgstpay ! application/x-rtp,media=application,payload=96,encoding-name=X-GST ! rtpbin.send_rtp_sink_0 \
rtpbin.send_rtp_src_0 ! udpsink port=5000 host=127.0.0.1 name=vrtpsink \
rtpbin.send_rtcp_src_0 ! udpsink port=5002 host=127.0.0.1 sync=false async=false name=vrtcpsink
The client pipeline looks like this:
gst-launch-1.0 -vvv rtpbin name=rtpbin \
udpsrc caps="application/x-rtp,payload=96,media=application,encoding-name=X-GST" port=5000 ! rtpbin.recv_rtp_sink_0 \
rtpbin. ! rtpgstdepay ! videoconvert ! autovideosink \
udpsrc port=5002 ! rtpbin.recv_rtcp_sink_0
rtpbin succesfully creates a sink and links to the udpsrc, but no stream comes out of rtp source pad.
The same pipeline without rtpbin can succesfully display the stream:
gst-launch-1.0 -vvv \
udpsrc caps="application/x-rtp,payload=96,media=application,encoding-name=X-GST" port=5000 ! \
rtpgstdepay ! videoconvert ! autovideosink
What an I doing wrong that rtpbin doesn't want to output the stream?
I also tried to replace the rtp_source part of the client with a fakesink to see if it would output anything, but still nothing comes out of rtpbin.

Answer 1

I found the solution to my problem. If any people come across the same problem, this is how to fix it:
First of all, rtpbin needs the clock-rate to be specified in the caps
When using rtpgst(de)pay, you need to specify the caps event string in your caps filter at the receiver, you can find this when printing the caps of the rtpgstpay element at the transmitter, eg:
application/x-rtp, media=(string)application, clock-rate=(int)90000, encoding-name=(string)X-GST, caps=(string)"dmlkZW8veC1yYXcsIGZvcm1hdD0oc3RyaW5nKUdSQVk4LCB3aWR0aD0oaW50KTY0MCwgaGVpZ2h0PShpbnQpNDYwLCBpbnRlcmxhY2UtbW9kZT0oc3RyaW5nKXByb2dyZXNzaXZlLCBwaXhlbC1hc3BlY3QtcmF0aW89KGZyYWN0aW9uKTEvMSwgY29sb3JpbWV0cnk9KHN0cmluZykxOjQ6MDowLCBmcmFtZXJhdGU9KGZyYWN0aW9uKTI1LzE\=", capsversion=(string)0, payload=(int)96, ssrc=(uint)2501988797, timestamp-offset=(uint)1970605309, seqnum-offset=(uint)2428, a-framerate=(string)25
So here the caps event string is
dmlkZW8veC1yYXcsIGZvcm1hdD0oc3RyaW5nKUdSQVk4LCB3aWR0aD0oaW50KTY0MCwgaGVpZ2h0PShpbnQpNDYwLCBpbnRlcmxhY2UtbW9kZT0oc3RyaW5nKXByb2dyZXNzaXZlLCBwaXhlbC1hc3BlY3QtcmF0aW89KGZyYWN0aW9uKTEvMSwgY29sb3JpbWV0cnk9KHN0cmluZykxOjQ6MDowLCBmcmFtZXJhdGU9KGZyYWN0aW9uKTI1LzE\=
When adding this to the caps at the receiver, you have to add a null terminator ( \0 ) at the end of the string.