Definition of the Opus Audio Codec (RFC6716)
Original Publication Date: 2012-Sep-01
Included in the Prior Art Database: 2012-Sep-11
Internet Society Requests For Comment (RFCs)
JM. Valin: AUTHOR [+3]
The Opus codec is a real-time interactive audio codec designed to meet the requirements described in [REQUIREMENTS]. It is composed of a layer based on Linear Prediction (LP) [LPC] and a layer based on the Modified Discrete Cosine Transform (MDCT) [MDCT]. The main idea behind using two layers is as follows: in speech, linear prediction techniques (such as Code-Excited Linear Prediction, or CELP) code low frequencies more efficiently than transform (e.g., MDCT) domain techniques, while the situation is reversed for music and higher speech frequencies. Thus, a codec with both layers available can operate over a wider range than either one alone and can achieve better quality by combining them than by using either one individually.
Internet Engineering Task Force (IETF) JM. Valin Request for Comments: 6716 Mozilla Corporation Category: Standards Track K. Vos ISSN: 2070-1721 Skype Technologies S.A. T. Terriberry Mozilla Corporation September 2012
Definition of the Opus Audio Codec
This document defines the Opus interactive speech and audio codec. Opus is designed to handle a wide range of interactive audio applications, including Voice over IP, videoconferencing, in-game chat, and even live, distributed music performances. It scales from low bitrate narrowband speech at 6 kbit/s to very high quality stereo music at 510 kbit/s. Opus uses both Linear Prediction (LP) and the Modified Discrete Cosine Transform (MDCT) to achieve good compression of both speech and music.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 5741.
Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at http://www.rfc-editor.org/info/rfc6716.
Valin, et al. Standards Track [Page 1]
RFC 6716 Interactive Audio Codec September 2012
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