使用 socket.io 流式传输网络摄像头

Question

I have been trying to implement a web application that will be able to handle following scenario:

• Streaming video/audio from a client to other clients (actually a particular set of them, no broadcasting) and server at the same time. The data source would be a webcam of the client.
• This streamed data has to be displayed in the real time on the other clients' browser and be saved on the server side for the 'archiving' purposes.
• It has to be implemented in node.js + socket.io environment.

To put it in some more specific context... The scenario is that there is a guy that makes a kind of a room for the users that he chooses. After the chosen users join the room, the creator starts streaming video/audio from his/her built in devices (webcam). All of the guests receive the data in real time, moreover the data is being sent to the server where it is stored so it can be recovered after the stream and room get closed.

I was thinking about mixing Socket.IO with WebRTC. In theory the combination of these two seem just perfect for the job. The Socket.IO is great for gathering specific set of users by assigning some sockets to a room and for signaling process demanded by the WebRTC. At the same time WebRTC is awesome for P2P connection between users gathered in the same room, it is also really easy to get access to the webcam and other built in devices that I might want to use.

So yeah, everything is looking pretty decent in theory but I would really need to see some code in action so I could actually try to implement it on my own. Moreover, I see some issues:

• How do I save the stream that is sent by the P2P connection? Obviously server does not have access to that. I was thinking that I might treat the server as another 'guest', so it would be just another endpoint of the P2P connection with the creator of the room. Somehow it feels edgy, though.
• Wouldn't it be better to treat server as the middleman between the creator and the clients? At one point there might be some, probably insignificant, delay comparing to P2P but presumably it would be the same for all the clients. (I tried that but I can't get the streaming from webcam to the server done, that's however is the topic for a different question as I am having problems with processing the MediaStream)

I was looking for some nice solutions but without any success. I have seen that there is this nice P2P solution made for socket.io: http://socket.io/blog/socket-io-p2p/ . The thing is - I don't think it will handle the data stream well. The examples mention only simple chat app and I need something a little bit heavier than that.

I would be really thankful for some specific examples, docs, whatever may lead me a little closer to the implementation of it as I really don't know how to approach it.

Thanks in advance :)

Answer 1

You task can be solved by using one of the open source WebRTC-servers. For example, kurento .

You can realize schemas of stream:

• One to one
• One to many
• Many to many

WebRtc-server schema

Clients will connect to each other through the WebRTC server. So, on server side you can record the stream, or send it for transcoding.

webSocket is used for communicating with server.

You can find some examples according to your task

Answer 2

Video streaming to multiple users is a really hard problem that unfortunately requires extensive infrastructure to achieve. You will not be able to stream video data through a websocket. WebRTC is also not a viable solution for what you are describing because, as you mentioned, the WebRTC protocol is P2P, as in the streaming user will need to make a direct connection to all the 'viewers'. This will obviously not scale beyond a few 'viewers'. WebRTC is more for direct video calls like in Skype for example.

Here is an article describing the architecture used by a somewhat popular live streaming service. As you can see achieving live video at any sort of scale will require considerable resources.