webrtc rust sample problem

[Jun Xiao]

Hi,

When I tried to run webrtc rust sample in ubuntu 22.04 VM by following
https://gitlab.freedesktop.org/gstreamer/gst-plugins-rs/-/tree/main/net/webrtc,
I met following problem:

$gst-launch-1.0 webrtcsink name=ws videotestsrc ! ws. audiotestsrc ! ws.
Setting pipeline to PAUSED ...
Pipeline is live and does not need PREROLL ...
Pipeline is PREROLLED ...
Setting pipeline to PLAYING ...
New clock: GstSystemClock
Redistribute latency...
Redistribute latency...
0:00:00.052590872  7339 0x7fb29006b8a0 ERROR             webrtcsink
net/webrtc/src/webrtcsink/imp.rs:2298:gstrswebrtc::webrtcsink::imp:<ws>
error: No caps found for stream video_0
ERROR: from element /GstPipeline:pipeline0/GstWebRTCSink:ws: There is
no codec present that can handle the stream's type.
Additional debug info:
net/webrtc/src/webrtcsink/imp.rs(2299): gstrswebrtc::webrtcsink::imp
(): /GstPipeline:pipeline0/GstWebRTCSink:ws:
Failed to look up output caps: No caps found for stream video_0
Execution ended after 0:00:00.036349323
Setting pipeline to NULL ...
Freeing pipeline ...

Could anyone share any suggestions?
Thanks,
Jun