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Wednesday, March 17, 2010

IETF First Draft for Codec Requirements

Members of the IETF Internet Wideband Audio Codec (CODEC) Working Grouphave released an initial level -00 Internet Draft specification for"Codec Requirements." Additional discussion (development process,evaluation, requirements conformance, intellectual property issues) isprovided in the draft for "Guidelines for the Codec Development Withinthe IETF." The IETF CODEC Working Group was formed recently to "toensure the existence of a single high-quality audio codec that isoptimized for use over the Internet and that can be widely implementedand easily distributed among application developers, service operators,and end users."
"According to reports from developers of Internet audio applicationsand operators of Internet audio services, there are no standardized,high-quality audio codecs that meet all of the following three conditions:(1) Are optimized for use in interactive Internet applications. (2) Arepublished by a recognized standards development organization (SDO) andtherefore subject to clear change control. (3) Can be widely implementedand easily distributed among application developers, service operators,and end users. According to application developers and service operators,an audio codec that meets all three of these would: enable protocoldesigners to more easily specify a mandatory-to-implement codec intheir protocols and thus improve interoperability; enable developersto more easily easily build innovative, interactive applications forthe Internet; enable service operators to more easily deploy affordable,high-quality audio services on the Internet; and enable end users ofInternet applications and services to enjoy an improved user experience.
The "Codec Requirements" specification provides requirements for an audiocodec designed specifically for use over the Internet. The requirementsattempt to address the needs of the most common Internet interactiveaudio transmission applications and to ensure good quality whenoperating in conditions that are typical for the Internet. Theserequirements address the quality, sampling rate, delay, bit-rate, andpacket loss robustness. Other desirable codec properties are consideredas well...
In-scope applications include: (1) Point to point calls -- where pointto point calls are voice over IP (VoIP) calls from two "standard" (fixedor mobile) phones, and implemented in hardware or software. (2)Conferencing, where conferencing applications that support multi-partycalls have additional requirements on top of the requirements forpoint-to-point calls; conferencing systems often have higher-fidelityaudio equipment and have greater network bandwidth available -- especiallywhen video transmission is involved. (3) Telepresence, where mosttelepresence applications can be considered to be essentially veryhigh-quality video-conferencing environments, so all of the conferencingrequirements also apply to telepresence. (4) Teleoperation, whereteleoperation applications are similar to telepresence, with theexception that they involve remote physical interactions. (5) In-gamevoice chat, where the requirements are similar to those of conferencing,with the main difference being that narrowband compatibility is notnecessary. (6) Live distributed music performances / Internet musiclessons, and other applications, where live music requires extremelylow end-to-end delay and is one of the most demanding application forinteractive audio transmission. also the IETF Internet Wideband Audio Codec (CODEC) Working Group Charter:

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