I tested the project on Nvidia Nano and desktop
(https://github.com/notedit/gstreamer-rtc-streamer). It is normal on the
desktop computer, but it is found that audio_sink_pad =
self.webrtc.get_request_pad('sink_%u') on line 129 of the webrtc.py file on
the Nvidia Nano returns None. Both systems are ubuntu18.04, and the
gstreamer is 1.14 .5, how can this problem exist?