Transmit voice chat from and to players

[philpax]

Players should be able to speak to each other naturally with their desired voice (#16 and #17). To achieve this, their voice needs to be streamed to the server, which then needs to stream it to other players, while preserving the quality of the input and with as low latency as possible.

I don't know how to do this. What are the codecs used for this? What do existing voice chat solutions do? Can one be integrated with ease, or do we have to roll our own?