ioquake3 VoIP support documentation.

Last updated 6/25/2008 by Ryan C. Gordon.

There are two ways to use VoIP in ioquake3. You can either use Mumble as an

external program, for which ioq3 now supplies some basic hooks, or you can

use the new built-in VoIP support.

Mumble is here: http://mumble.sourceforge.net/ ... ioquake3 can supply it

with your in-game position, but everything else is whatever features Mumble

offers outside of the game. To use it, start Mumble before you start ioq3,

and run the game with +set cl_useMumble 1. This should work on at least

Linux, Mac OS X, and Windows, and probably other platforms Mumble supports

in the future.

The built-in stuff offers tighter in-game integration, works on any platform

that ioquake3 supports, and doesn't require anything more than a recent build

of the game. The rest of this document is concerned with the built-in VoIP

support.

Quick start for servers:

- run a recent build of ioquake3.

- Make sure your network settings are set to broadband.

Quick start for clients:

- run a recent build of ioquake3.

- Make sure your network settings are set to broadband.

- +set s_useOpenAL 1

- \bind q "+voiprecord"

- Hook up a microphone, connect to a VoIP-supporting server.

- hold down 'q' key and talk.

Cvars you can set:

sv_voip: set to "1" (the default) to enable server-side VoIP support. Set to

"0" to disable. Without this, all VoIP packets are refused by the

server, which means no one gets to use in-game VoIP.

cl_voip: set to "1" (the default) to enable client-side VoIP support. Set to "0"

to disable. Without this, you will neither be able to transmit voice nor

hear other people.

s_alCapture: set to "1" (the default) to have the audio layer open an OpenAL

capture device. Without this set on sound startup, you'll never

get bits from the microphone. This means you won't transmit, but

you can still hear other people.

cl_voipSendTarget: a string: "all" to broadcast to everyone, "none" to send

to no one, "attacker" to send to the last person that hit

you, "crosshair" to send to the people currently in your

crosshair, or a comma-separated list of client numbers, like

"0,7,2,23" ... an empty string is treated like "all". This

is reset to "all" when connecting to a new server.

Presumably mods will manage this cvar, not people, but

keybind could be useful for the general cases. To send to

just your team, or the opposing team, or a buddy list, you

have to set a list of numbers.

cl_voipUseVAD: set to "1" to automatically send audio when the game thinks you

are talking, "0" (the default) to require the user to manually

start transmitting, presumably with a keybind.

cl_voipVADThreshold: only used if cl_voipUseVAD is "1" ... a value between

0.0 and 1.0 that signifies the volume of recorded audio

that the game considers to be speech. You can use this

to trim out breathing or perhaps the sound of your

fingers tapping the keyboard and only transmit audio

louder than that. You will have to experiment to find the

value that works best for your hardware and play style.

The default is "0.25", with "0.0" being silence and "1.0"

being pretty-darn-loud.

cl_voipSend: when set to "1", the game will capture audio from the microphone

and transmit it, when "0", the game will not. The game can

optimize for the "0" case (perhaps turning off audio recording).

Lots of things set this on and off, including cl_voipUseVAD, so

you probably should not touch this directly without knowing what

you're doing, but perhaps mods can make use of it.

cl_voipGainDuringCapture: This is the volume ("gain") of audio coming out of

your speakers while you are recording sound for

transmission. This is a value between 0.0 and 1.0,

zero being silence and one being no reduction in

volume. This prevents audio feedback and echo and

such, but if you're listening in headphones that

your mic won't pick up, you don't need to turn down

the gain. Default is 0.2 (20% of normal volume). You

ABSOLUTELY want to make your speakers quiet when you

record, if the microphone might pick it up!

cl_voipShowMeter: Set to "1" (the default) to show a volume meter as you are

recording from the microphone, so you can see how well the

game can "hear" you. Set to "0" to disable the display of

the meter.

cl_voipCaptureMult: Multiply recorded audio by this value after denoising.

Defaults to 2.0 to _double_ the volume of your voice.

This is to make you more audible if denoising eats away

too much data. Set this to 1.0 to get no change, less to

be quieter.

Console commands:

voip ignore <clientnum>

Turn off incoming voice from player number <clientnum>. This will refuse to

play any incoming audio from that player, and instruct the server to stop

sending it, to save bandwidth. Use unignore to reenable. This is reset to

unignored when (re)connecting to a server.

voip unignore <clientnum>

Turn on incoming voice from player number <clientnum>. This will start

playing audio from this player again if you've previously done a "voip

ignore", and instruct the server to start sending her voice packets to

you again.

voip muteall

Turn off all incoming voice. This will refuse to play any incoming audio,

and instruct the server to stop sending it, to save bandwidth. Use

unmuteall to reenable. This is reset to unmuted when (re)connecting to

a server.

voip unmuteall

Turn on incoming voice. This will start playing audio again if you've

previously done a "voip muteall", and instruct the server to start

sending voice packets to you again.

voip gain <clientnum> <gain>

Sets the volume ("gain") for player number <clientnum> to <gain> ...

A gain of 0.0 is silence, and 2.0 doubles the volume. Use this if someone

is too quiet or too loud.

Actions:

+voiprecord: The action you should bind to a key to record. This basically

toggles cl_voipSend on and off. You don't need this if you're

using cl_voipUseVAD, since that'll just record all the time and

decide what parts of the recording are worth sending.

More detailed/technical info:

By default, all of this is enabled. You can build with or without VoIP

support explicitly with USE_VOIP=[1|0] on the make command line.

You currently must use OpenAL to speak, as we have ALC_EXT_capture support

in place to pull data from the microphone. If you are using the SDL backend,

you can still hear people, but not speak.

There is no in-game UI to speak of: we encourage mods to add some. Largely

they will just need to set cvars and run console commands for choosing

voice targets and ignoring people, etc.

This requires patched builds to be useful, but remains network compatible with

legacy quake3 clients and servers. Clients and servers both report in their

info strings whether they support VoIP, and won't send VoIP data to those not

reporting support. If a stray VoIP packet makes it to a legacy build, it will

be ignored without incident.

VoIP packets are saved in demo files! You will be able to playback what you

heard and what you said on VoIP-compatible clients. Legacy clients can also

play demo files with VoIP packets in them, but just won't play the voice

track. For VoIP-supported builds, it's nice to have a record of the

trash-talk.

Data is processed using the Speex narrowband codec, and is cross-platform.

Bigendian and littleendian systems can speak to each other, as can 32 and

64-bit platforms.

Bandwidth: VoIP data is broken up into 20 millisecond frames (this is a Speex

requirement), and we try to push up to 12 Speex frames in one UDP packet

(about a quarter of a second of audio)...we're using the narrowband codec:

8000Hz sample rate. In practice, a client should send about 2 kilobytes per

second more when speaking, spread over about four bursts per second, plus a

few bytes of state information. For comparison, this is less than the server

sends when downloading files to the client without an http redirect. The

server needs to rebroadcast the packet to all clients that should receive it

(which may be less than the total connected players), so servers should

assume they'll need to push (number of players speaking at once times number

of people that should hear it) * 2 kilobytes per second. It shouldn't be a

problem for any client or server on a broadband connection, although it may

be painful for dialup users (but then again, everything is. They can just

disable the cvar). The game will refuse to enable VoIP support if your have

your network settings lower than "Cable/xDSL/LAN", just in case.

The initial VoIP work was done by Ryan C. Gordon <icculus@icculus.org>, and

he can be contacted with technical questions, if the ioq3 mailing list or

forums aren't helpful.

// end of voip-README.txt ...