node-webrtc-examples
This project presents a few example applications using node-webrtc.
- audio-video-loopback: relays incoming audio and video using RTCRtpTransceivers.
- ping-pong: simple RTCDataChannel ping/pong example.
- pitch-detector: pitch detector implemented using RTCAudioSink and RTCDataChannel.
- sine-wave: generates a sine wave using RTCAudioSource; frequency control implemented using RTCDataChannel.
- sine-wave-stereo: generates a stereo sine wave using RTCAudioSource; panning control implemented using RTCDataChannel.
- video-compositing: uses RTCVideoSink, node-canvas, and RTCVideoSource to draw spinning text on top of an incoming video.
- record-audio-video-stream using FFmpeg and RTCVideoSink.
- Broadcast example with one broadcaster forwarding to many viewers.
Usage
Install the project's dependencies and run the tests before starting the application server:
npm install
npm test
npm start
Then, navigate to http://localhost:3000.
Architecture
Each example application under examples/ has a Client and Server component. RTCPeerConnection negotiation is supported via a REST API (described below), and is abstracted away from each example application. Code for RTCPeerConnection negotiation lives under lib/.
RTCPeerConnection Negotiation
RTCPeerConnections are negotiated via REST API. The Server always offers (with
host candidates) and the Client always answers. In order to negotiate a new
RTCPeerConnection, the Client first POSTs to /connections. The Server responds
with an RTCPeerConnection ID and SDP offer. Finally, the Client POSTs an SDP
answer to the RTCPeerConnection's URL.
Client Server
| |
| POST /connections |
| |
|---------------------------------------------------->|
| |
| 200 OK |
| { "id": "$ID", "localDescription": "$SDP_OFFER" } |
| |
|<----------------------------------------------------|
| |
| POST /connections/$ID/remote-description |
| $SDP_ANSWER |
| |
|---------------------------------------------------->|
| |
| 200 OK |
| |
|<----------------------------------------------------|
RTCPeerConnection Teardown
RTCPeerConnections can be proactively torn down by sending a DELETE to the
RTCPeerConnection's URL; otherwise, ICE disconnection or failure, if unresolved
within the timeToReconnect window, will also trigger teardown. The default
timeToReconnect value is 10 s.
Client Server
| |
| DELETE /connections/$ID |
| |
|---------------------------------------------------->|
| |
| 200 OK |
| |
|<----------------------------------------------------|