Short answer is, no. RTSP
is not mentioned in the IETF standard for WebRTC and no browser currently has plans to support it. Link to Chrome discussion.
Longer answer is that if you are truly sold out on this idea, you will have to build a webrtc gateway/breaker utilizing the native WebRTC API.
- Start a WebRTC session between you browser and your breaker
- Grab the IP Camera feed with your gateway/breaker
- Encrypt and push the rtp stream to your WebRTC session from your RTSP stream gathered by the breaker through the WebRTC API.
This is how others have done it and how it will have to be done.
UPDATE 7/30/2014:
I have experimented with the janus-gateway and I believe the streaming plugin does EXACTLY this as it can grab an rtp stream and push it to an webrtc peer. For RTSP, you could probably create RTSP client(possibly using a library like gstreamer), then push the RTP and RTCP from the connection to the WebRTC peer.