WebRTC generate invalid rtpmap for H264

[Peter Biro]

Hi all,

I found a pretty strange issue webrtcbin generates the following initial SDP offer with a negative clock rate:

v=0
o=- 5716970113760455593 0 IN IP4 0.0.0.0
s=-
t=0 0
a=ice-options:trickle
a=msid-semantic:WMS webrtc_sink
m=video 9 UDP/TLS/RTP/SAVPF 96
c=IN IP4 0.0.0.0
a=setup:actpass
a=ice-ufrag:0ybqQZNeS9CznnGxJxW/BpKyapc+CXsL
a=ice-pwd:ffvVDjwSJ7/+AAdh3MjUMMhz91xwZZGI
a=sendrecv
a=rtcp-mux
a=rtcp-rsize
a=rtpmap:96 H264/-1784864736
a=rtcp-fb:96 nack pli
a=mid:video0
a=fingerprint:sha-256 9B:11:48:BE:41:FF:CA:FE:62:B1:98:07:7B:E6:80:2A:56:9A:56:DC:A2:60:81:27:DE:EC:F5:76:C1:C4:39:51

Actually it is more like a random number it changes in every session setup. However as I see it should be set to 9000.

My pipleine is pretty simple:

nvarguscamerasrc sensor-id=0 sensor-mode=0 gainrange="1 16" ispdigitalgainrange="1 1"
    ! video/x-raw(memory:NVMM), width=(int)1920, height=(int)1080, format=(string)NV12, framerate=(fraction)30/1
    ! nvvidconv ! nvv4l2h264enc bitrate=8000000 control-rate=1 insert-sps-pps=true ! rtph264pay mtu=1400 
    ! webrtcbin name=webrtc_sink latency=0

And on the application side Im handling the singling. 

Do you have any idea how to fix this? What I am missing here?

Thanks,
Peter