Voice

Voice is a feature that made its debut on its own grid and beta viewer in March of 2007[1].

Frequently Asked Questions

There's an exhaustive Voice FAQ which provides answers to many questions about the new voice feature.

Groups

The Voice Mentors group and Voice in SL: A Community Forum are advocacy and help groups for users having problems adjusting to the new system.

Technical

Voice in Second Life uses Vivox technology that is based on RTP (using the oRTP library), SIP (using the amsip library from Antisip), OpenAL, TinyXPath, OpenSSL, and libcurl for the transmission of voice data. The positional 3D audio is achieved with technology from DiamondWare. These technologies are contained in external daemon software that is started and stopped by the Second Life client.

The SecondLife viewer handles configuration, control, and display functions, but the voice streams (from the microphone and from the Vivox voice server) do not enter the viewer. Unfortunately the source code for the external SLVoice daemon is not available due to contractual obligations between Linden Labs and Vivox.

The executables can be found in the Program Files\SecondLife directory of the runtime and in the linden\indra\newview\vivox-runtime\(platform) directory of the source distribution.

• SLVoice.exe
  • Thin wrapper around the Vivox SDK
  • Launched when voice is enabled in SL
  • Runs a TCP server that listens and replies to commands and queries using an XML format
• SLVoiceAgent.exe
  • Actually called the DiamondWare Thin Voice Client
  • Launched by SLVoice
  • Unclear how this fits in the communication chain
• vivoxsdk.dll
  • The Vivox SDK
  • Used by SLVoice.exe
  • Uses a solution from Antisip for SIP, RTP, and G.711
  • Uses OpenAL for playing and recording audio
  • Additionally implements the G.722.1/C (aka Siren14) codec
• ortp.dll
  • Real-time Transport Protocol (RFC3550) stack under LGPL
  • Used by vivoxsdk.dll
  • Originally from Linphone
  • Distributed as part of amsip by Antisip
• wrap_oal.dll
  • OpenAL, a cross-platform 3D audio API
  • Used by vivoxsdk.dll
• alut.dll
  • The OpenAL Utility Toolkit (ALUT)
  • Used by vivoxsdk.dll
• ssleay32.dll and libeay32
  • From the OpenSSL Project, a collaborative effort to develop a robust, commercial-grade, full-featured, and Open Source toolkit implementing the Secure Sockets Layer (SSL v2/v3) and Transport Layer Security (TLS v1) protocols as well as a full-strength general purpose cryptography library.
  • Used by SLVoiceAgent.dll
• tntk.dll and srtp.dll
  • Part of the DiamondWare distribution
  • Apparently not used

See also: Third Party Libraries