Robust Audio Tool (RAT)

The Robust Audio Tool (RAT) is a an open-source audio conferencing and streaming application that allows users to particpate in audio conferences over the internet. These can be between two participants directly, or between a group of participants on a common multicast group.

RAT require no special features for point-to-point communication, just a network connection and a soundcard. For multiparty conferencing RAT uses IP multicast and therefore all participants must reside on a multicast capable network. RAT is based on IETF standards, using RTP above UDP/IP as its transport protocol, and conforming to the RTP profile for audio and video conference with minimal control.

RAT features a range of different rate and quality codecs, receiver based loss concealment to mask packet losses, and sender based channel coding in the form of redundant audio transmission. It offers better sound quality relative to the network conditions than most audio tools available. It also features encryption so you can keep your conversations private.

RAT runs on a range of platforms: FreeBSD, HP-UX, IRIX, Linux, NetBSD, Solaris, SunOS, and Windows 95/NT.

The source code is publicly available for porting to other platforms and for modification by others. Later releases (4.x) have an open source license. Source code can be obtained from the download page and by anonymous CVS.

RAT is just an audio application, it does not perform call services like user location, neither does it listen to session announcements to discover advertised multicast sessions. For these purposes, it is recommended you use RAT in conjunction with the Session Directory (SDR), or a similar application.