Support for Voice and Video within the various IM Services

Within the scope of Voice and Video, there are a number of different types of capabilities which are each supported to a different extent by the various Instant Messaging platforms.

AIM Client

 AIM (AOL Instant Messenger) supports video chat for both the Windows and Mac OS X platform. The audio chat and telephony capabilities are available on the Windows platform only.

iChat

 iChat is the built-in component of Mac OS X built by Apple. It supports a full range of audio and video chat in single and multiple user configurations. The video chat is compatible with AIM, and all voice and video chats can be held with other Apple users who are using Jabber, Rendezvous, or AIM protocols.

Yahoo! Messenger

 Yahoo! Messenger Supports Video Chat (WebCam) on both the Mac and Windows platforms. There are two severe limitations to their implementation. The first is that there is no sound capability to go with the Video Chat. Secondly, the Video chat is implemented as a series of JPEG2000 images which are posted to the Yahoo website and available for download by clients. There is no attempt at time synchronization, so the video is very jittery, and the frame rate is quite low.

Yahoo supports voice chat and telephony services on the Windows platform, but it is not available on MacOS X.

MSN Messenger

 MSN Messenger (Also known as Windows Messenger and Windows Live Messenger) Has voice, video, and telephony features available for the Windows platform, and uses proprietary CODECs which will make it difficult to run on Mac OS X.

Google Talk Client

 Google Talk (gtalk) is a Jabber/XMPP based client available for Windows which facilitates voice communication among google users. Although the client is Windows only, they have released the protocol specification under the name jingle and sample source code (libjingle) to allow other Jabber/XMPP clients to easily implement the voice chat capabilities.

Skype

 Skype is built primarily as a telephony (PC to Telephone) communication system. It can support inbound and outbound phone calls as well as voice and text communication directly with other Computer users on Windows, Mac OS X and Linux. It offers multi-user voice conferencing as well as video chat for computer users. This is based upon the Kazaa peer-to-peer file sharing protocols, which are obfuscated using a secret encrypted protocol, so it will be difficult to integrate into Adium.

Gizmo Project

 Gizmo Project is very similar to Skype except that it does not have video chat capabilities. It is built using the open SIP protocol and should be fairly easy to integrate into Adium (see below).

Ventrilo

 Ventrilo is a Voice Messaging system which can be thought of as IRC with Voice capabilities. This business model is based upon selling server software and allowing free use of the software. It relies upon someone purchasing the server software and putting it on a machine with sufficient bandwidth for the voice communication.

The communication model is based upon "rooms" where everyone can hear all other participants in that room.

TeamSpeak

 TeamSpeak is very similar to Ventrilo, and the feature set and business model is nearly identical. Because of the choice of CODECs used, Ventrilo can have slightly better sound quality on Windows, but the TeamSpeak server is easier to administer.

VoIP / SIP

 VoIP (Voice over Internet Protocol) is a common set of open protocols (most importantly  SIP) which allows interoperability between devices wanting to communicate using voice over Internet Networks. These protocols have been implemented by large telephone handset manufacturers such as Cisco, service providers such as Vonage as well as PBX manufacturers such as  Asterisk. Some other clients like Gizmo Project also allow your computer to act as a VoIP terminal.

H.323 Video Conferencing

 H.323 is a set of ITU standards, primarily used in connecting Video Conferencing hardware across the public telephone network. In recent years, it has expanded to include Internet based protocols and the boundaries are beginning to blur between this specification and VoIP.

Service Capabilities Matrix

	AIM	iChat	Yahoo	MSN	Google Talk	Skype	Gizmo Project	Ventrillo	Team Speak	VoIP	H.323
Voice Chat
One Way Voice Chat
Multi-User voice Conference
Video Chat			(no sound)
Multi-User Video Chat			(no sound)
One Way Video Chat			(no sound)
Computer to Telephone Calls
Telephone to Computer Calls