CELT: A Low-latency, High-quality Audio Codec
Channel: Linux.conf.au 2009 -- Hobart, Australia
Date: 2014-12-08

Presenter(s): Timothy Terriberry
URL: http://www.linux.org.au/conf/2009/programme/schedule/view_talk/187%3Fday=thursday.html

(with Jean-Marc Valin)Ever wondered why your telephone doesn't sound as good as your music player? Historically, low-latency speech codecs such as Speex have had poor performance on music or other general audio, since the techniques they use do not scale well to high sampling rates. High quality general purpose codecs such as Vorbis have too high a latency to be used for telephony. We present a new codec, CELT, which has both extremely low latency and good quality at high sampling rates. This makes it possible to play live music together with someone over a DSL connection or enjoy "CD-quality" video conferencing, and enables or enhances a host of other interactive applications. Unlike mainstream audio and video, there is no entrenched proprietary codec in this domain, and our open source alternative is already better than the competition.This talk will explain why latency is an issue in interactive applications, briefly describe how we were able to extend the techniques used in speech codecs beyond the sampling rates where they are traditionally effective, and talk about the libcelt API and how to write low-latency audio applications for Linux. It will include a live demo of the codec.

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