Free Code Chat Software

A range of software related to voice and video chat, originally aggregated by Danyl Strype as part of research for Core Us, a proposed Disintermedia project for empowering global scale organizing using free code voice and video chat tools, including increasing the ability of conferences to support remote participation.

Audio only

• Adhearsion Foundation: a whole stack of web telephony software projects, although as of late 2019, only Adhearsion itself and Blather have recent commits, and most of them seem to have ceased development in late 2015/ 2016 (including Candy). There's been no updates on the Foundation website since then either.

• GNUComm and GNU Telephony (GPL 2 or later): A suite of telephony software supported by the GNU Project, which includes 7 GNU projects: Bayonne, SIP Witch, and their supporting libraries (Common C++ / uCommon, ccAudio, ccScript, ccRTP, and ZRTP / ZRTP4J). The GNU Telephony website appears to have gone down and the page on gnu.org has no updates on development progress since 2013.

• Mumble/ Murmur (New BSD): an 'IRC with voice' style system, developed for in-game chat

• SIPML5 (BSD, formerly GPLv3) and WebRTC2SIP: A SIP client written in Javascript, and a WebRTC back-end allowing the browser to be a phone.

• YATE (GPL v2): Internet telephony engine designed to be easily extensible.

Video-only

Video only

HasciiCam (C, GPL?): Uses the AA-Lib library to convert video from a camera (eg web cam) into ASCII text, which can be transferred across a network and displayed without much lower use of resources than a full-data video stream.

Jitsi VideoBridge (LGPL, switching to Apache license): video relaying server for multiparty conferences. Audio-visual:

Audio-visual

BigBlueButton (LGPL): voice/video web conferencing server developed for distance education. Currently depends on Flash, but has a rough plan for full transition to HTML5 and WebRTC.

Eventstreamr (GNU AGPL): "single and multi room audio visual stream management"

GNU Jami: P2P text, voice, and video chat client, cross-platform (desktop and mobile)

Jitsi Meet (MIT, switching to Apache license): WebRTC client for text, voice and video conferencing, encrypted by default, with desktop and presentation sharing.

NextCloud Talk (AGPL): a WebRTC plug-in for the NextCloud app suite

OpenCast (Educational Community License 2.0, a variant of Apache 2.0): Java/ HTML system developed for use in recording and streaming university lectures by the Apero Foundation.

Palava.tv: Uses the Palava-machine (Ruby) and Palava-client (CoffeeScript) listed on the FSF Free Software Directory.

RetroShare (components under a range of libre licenses): A P2P communications client which can support both voice and video chat

RocketChat (MIT): a web-based chat server billed as a "Slack-like online chat, built with Meteor". It supports WebRTC for voice/ video conferencing, with a plug-in for Jitsi Videobridge to increase the number of users it can support in a conference.

Signal (client apps: GPLv3, server: AGPLv3): Developed by Open Whisper Systems, Signal consists of apps for Android and iOS and a routing server, end-to-end encrypted by default.

Spreed (AGPLv3): A WebRTC server for voice and video calls and conferencing, using Go and Node.JS.

Subrosa (GPLv3, discontinued): WebRTC client/server for text, voice and video conferencing, encrypted by default.

Talky.io: A WebRTC platform which has released a number of elements of their stack as free code including SimpleWebRTC and OTalk (although there are still some proprietary bits in the stack).

Tox: encrypted, cross-platform, peer-to-peer, text, voice, and video chat. Client software for various platforms, in various languages, mostly still in alpha/ beta, built around Toxcore (C, GPLv3)

UnHangout (GPL): Developed at MIT, specifically as a replacement for the goOgle product with a similar name. Seems to be a JS-based web interface built around a Jitsi Meet core.

Wire (GPL): encrypted one-to-one and group chat, with encryption. Has both web app and desktop/ mobile apps. Live mixers

Live mixers

dvswitch (GNU GPL): an audio-visual mixing system that depends on LibAV

gst-switch (GNU GPL): written in C and uses GStreamer

snowmix (GNU GPLv3)

Voctomix (Expat or "MIT") a live video mixer wrapped around GStreamer (GNU LGPL), developed by the C3VOC in response to their frustrations with dvswitch, snowmix and gst-switch

Standards/ Protocols

Jingle (open protocol extending XMPP): designed for one-on-one voice/ video chat

Muji (open protocol extending Jingle): allow for multi-user voice chat

SIP (Session Initiation Protocol): a server/client protocol mainly used for voice chat

Tox: peer-to-peer, encrypted, text, voice, and video chat.

XMPP (eXtensible Messaging and Presence Protocol): client/server protocol for Instant Messaging (short emails in realtime) based on Jabber

WebRTC: An open standard developed by Google, Mozilla, and Opera for realtime voice and video conversation, which is being standardized by the W3C. Some documentation on how to implement can be found on WebRTC Quick Start.

Codecs

If we are going to stream, store and replay audio and video from conferences, we don't want to use patent-encumbered, proprietary formats like MP3, and H.264. Instead, we want to use patent-free/ royalty-free multimedia file formats, developed by groups like Xiph.org.

Some existing options are:

Audio

• Opus - developed by Xiph (replaces Speex)
• Vorbis - developed by Xiph, lossy codec (equivalent to MP3, also obsoleted by Opus?)
• FLAC - developed by Xiph, lossless codec

Video

• Theora - developed by Xiph
• Dirac - created by BBC Research, "low-resolution web content to broadcasting HD and beyond, to near-lossless studio editing"
• VP8/ VP9 - bought by Google and released as a royalty-free open codec

Containers

Formats which allow video, audio, subtitles and other components in different formats to be one included in one file

• Ogg - developed by Xiph
• Matroska - developed by the Matroska organisation in France
• WebM - developed by Google, uses a fork of the Matroska container, VP8 (or 9) video, Vorbis or Opus audio, and WebVTT for text

Peer-to-Peer Network

Whatever end-user applications and codecs are used, it seems reasonable that any conferencing system will be more scalable if it uses some kind of P2P network, where everyone who joins the conference contributes some of their own computing resources to the networking effort. This is how Skype originally worked, before Microsoft acquired it and moved it to a purely client/server model. Some existing open P2P network protocols that could be used:

FreeNet (GPL): uses standard IP networking in an attempt to create an uncensorable alternative to the world wide web,

GNUNet (GPL): "GNU's Framework for Secure Peer-to-Peer Networking",

BitTorrent Live: A system for streaming live events using the same P2P swarming principles underlying BitTorrent downloads

Retroshare (GPL): "using a web-of-trust to authenticate peers and OpenSSL to encrypt all communication... provides filesharing, chat, messages, forums and channels

See also:

• Chatting, Audio and Video Calls: A document by RiseUp Labs, the folks behind We.Riseup.net
• 74 free code telephony projects from 2007