Question What is the point of Vivox/Agora vs. WebRTC? (for purely audio comms)

mikejm_ · Jul 4, 2023

I am trying to figure out the best/cheapest/simplest technology for multiplayer voice communication.

As I understand, Unity WebRTC allows for direct peer to peer audio connections. One could presumably scale the volume of audio connected players or mute/adjust them based on proximity or other factors based on gameplay in Unity via script once connections are made.

For example doing something like: https://assetstore.unity.com/packages/tools/network/voice-chat-multiplayer-netcode-webrtc-248159

So if the only need is to get an audio connection between your users, what is the point of something like Vivox/Agora?

Specifically on a tech level for audio chat what is Vivox/Agora doing? Is it just facilitating peer to peer WebRTC connections just like I described? Or is it sending all the audio to a single server and the server is mixing the individual streams per player (or forwarding all the individual streams again to each player)?

From a cost perspective, peer to peer audio will also save server costs. If it is taking all the audio streams as an intermediary to the server, why? Why pay data charges of sending audio to an intermediary server if one does not need to?

Thanks for any clarity.

CodeSmile · Jul 4, 2023

I don‘t know about audio but since a WebGL app cannot be a server/host in a network game I would assume there is no peer to peer connectivity possible between two WebGL apps without an intermediate server service.

WebRTC doesn‘t do peer to peer, it requires a server too:

For most WebRTC applications to function a server is required for relaying the traffic between peers, since a direct socket is often not possible between the clients (unless they reside on the same local network). The common way to solve this is by using a TURN server. The term stands for Traversal Using Relays around NAT, and it is a protocol for relaying network traffic.
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mikejm_ · Jul 5, 2023

CodeSmile said: ↑

I don‘t know about audio but since a WebGL app cannot be a server/host in a network game I would assume there is no peer to peer connectivity possible between two WebGL apps without an intermediate server service.

WebRTC doesn‘t do peer to peer, it requires a server too:
Click to expand...

Thanks. I'm just learning as I go. I found this good summary that explains it:

https://getstream.io/glossary/turn-server/

A TURN server acts as an intermediary that relays packets of media data from one device to another. By using these relays, the TURN server can work around firewalls and other security measures that prevent devices from making a direct connection.

The best way to understand how a TURN server works in practice is by first looking at how STUN servers connect devices. The STUN server works much like a phone operator. It introduces different devices to each other by using each device's public IP address as its name. Once the introduction has been made, the devices can connect directly to each other and begin sharing data without further assistance from the server.

But if a device has a hidden or private IP address, then the STUN server won't be able to identify it properly or introduce it to other devices. And without the introduction, the devices won't know how to get in touch with each other to send data. When this happens, devices can turn to the TURN server rather than trying to form a direct connection with each other.

The TURN server receives packages of data from one device, then re-packages and sends it to another device. Rather than acting as an operator like its STUN counterpart, a TURN server acts more like a mail delivery service. One device sends the TURN server a message. Then the server sends the message to another device. This allows devices to communicate with each other without compromising the security measures they may have in place.
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So to the extent that one is able, if your users can connect with STUN you will save on data costs as they will be sending the data directly to one another. But if you need TURN you will have to pay for every player second of audio transmitted in any direction at a time.

Presumably things like Vivox and Agora are doing TURN by default? I wonder. I wonder also how Unity WebRTC works with either or both. I will have to learn more.

Anyone know anything about any of this? Thanks.

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Question What is the point of Vivox/Agora vs. WebRTC? (for purely audio comms)

mikejm_

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