Stream real time video from local IP to browser in an external network using websocket/webRTC with raspberry pi 3b+

0
votes

Anybody here with some experience in websockets and webRTC using TURN/STUN servers?

Requirement: Send real-time video feed from local IP to browser in an external network and I need some help implementing via raspberry pi 3b+. My camera source is android device, and using 3rd party apps I am able to generate the video feed over local network. Using the same app I can stream via Youtube Live,but getting a latency of about 2 secs in ultra low latency mode and dvr enabled. And I am trying to reduce the latency of the stream.

Q1. Do the semi-public TURN server provide a one to one peer. Or anyone can just jump into the URL and view and override what I am streaming?Please provide few list of service providers.

Just for information there would be 1-2 users browser connected at max.

Q2. Do I need Janus gateway to send webRTC/websockets data into the TURN/STUN server? Since my raspberry is connected to a different network and I cannot port forward due to carrier constraints.

Q3. Do I need both STUN/TURN servers or do I even need webRTC instead of websockets to send my video stream over the internet. Is websockets not sufficient?

Q4. Since we are not implementing over local network do we need to install coTURN too on raspberry pi?

Q5. Is there any android app that can publish the data from camera to websocket/werRTC server with a public ws URL?

Any help would be really helpful.

1
websocketraspberry-piwebrtcstunjanus-gateway

1 Answers

1
votes

Q1. TURN servers relay media. They do this by allocating for every connecting peer a relay port between 49152–65535. This relay port will then be used to transmit the media to the second peer. The peers will know which relay ports to use automatically since this is part of the ice gathering process. To get back to your question: Other Peers cannot write to that relay port, it is 1 to 1 with handshakes, there is no chance of someone else overwriting it.

Q2. You definitely do not need a Janus Gateway to use TURN. TURN and STUN will probably work fine for NAT-Traversal without port forwarding.

Q3. You need at least a TURN server (but you ideally want to use 1 STUN server and 1 TURN server). STUN will work in most cases, but will fail if there are firewalls or complicated NATs, which block inbound udp connections. TURN is just the fallback for those cases. Needing WebRTC? For just streaming videos, it depends on the use case. A sequence of images can be transmitted over websockets, they can handle Blobs fine. But you won't have a very fluent, high fps AND high resolution video stream this way. And of course, I know of no usable way to transmit audio over websocket.

Q4. The raspberry pi is a Peer that transmits media? Peers do not need a local TURN server installation, you will only need 1 TURN server (which should not be behind a NAT, probably running on some web server). The TURN server is a separate instance.
EDIT
For your private testing and development purposes, you may use https://numb.viagenie.ca/ . I don't know much about commercial turn server hosters, except that some exist. For someone who owns a v-server or root server, installing coTURN may be an option, this Tutorial might be helpful. To check if the server is working, I also found this snippet to be very useful.
END EDIT

Q5. There is no android app that publishes webRTC streams to a ws URL since websocket messages are used by webrtc only for signalling (that is, telling peers their host candidates, those are the IP adresses and ports learned by the ice gathering process, this includes the TURN and STUN ip and port combinations).