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<!DOCTYPE doctype PUBLIC "-//w3c//dtd html 4.0 transitional//en"><html><head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<meta name="GENERATOR" content="Mozilla/4.78 [fr] (X11; U; Linux 2.4.17 i686) [Netscape]">
<meta name="Author" content="Jean-Marc Valin">
<title>The Speex Speech Codec</title>
</head>
<body text="#000000" bgcolor="#ffffff" link="#0000ef" vlink="#59188e" alink="#ff0000">
<center>
<img src="speex.png" alt="Speex">
</center>
<br>
<br>
<a href="http://sourceforge.net/projects/speex">The Speex project</a>
aims to build an open-source (LGPL) <A href="patents.html">patent-free</A> voice codec. Unlike
other codecs like MP3 and <a href="http://www.vorbis.org/">Ogg Vorbis</a>, Speex is specially designed for compressing voice at low bit-rates
for applications such as voice over IP (VoIP). In some sense, it is meant
to be complementary to the Ogg Vorbis codec.
<p>If you are interested in participating to the project, contact us at <a href="mailto:speex-devel@lists.sourceforge.net">
speex-devel@lists.sourceforge.net</a> or <a href="http://lists.sourceforge.net/lists/listinfo/speex-devel">
join our mailing list</a>. Right now, we are mostly looking for
developers with signal processing and speech coding knowledge, as well
as people with knowledge about patents in that field. See the
<A href="http://sourceforge.net/pm/task.php?group_project_id=19556&group_id=46651&func=browse">task list</A> for more details about what's left to do in Speex<br>
</p>
<h2>Download</h2>
You can download Speex from <a href="http://sourceforge.net/project/showfiles.php?group_id=46651">
here</a>.<br>
<h2>Documentation</h2>
This Speex manual includes information about the
algorithms used in Speex, the bit-stream, the API and more.
<br>
<A href="manual.pdf">Speex manual (PDF)</A>
<br>
<A href="manual.ps">Speex manual (Postscript)</A>
<br>
<A href="manual/">Speex manual (HTML online)</A>
<br>
<A href="manual.tar.gz">Speex manual (HTML tarball)</A>
<h2>Samples</h2>
You can listen to samples encoded with Speex <A href="/audio/samples/">here</A>
<h2>Who uses Speex</h2>
<A href="http://www.linphone.org">LinPhone</a>: A SIP-based VoIP phone written for GNOME
<br>
<A href="http://jzb.rapanden.dk/speex/">Speex XMMS plugin</a> written by <a href="mailto:jzb@rapanden.dk">Jens Burkal</a>
<br>
<A href="http://www.openh323.org">OpenH323</a>: An open-source H.323 stack
<br><br>
In development:
<br>
<A href="http://www.asteriskpbx.org">Asterisk</a>: An open-source PBX
<br>
<A href="http://www.gnomemeeting.org">GnomeMeeting</A>: A H323 Video Conferencing Program
<h2>News</h2>
<h3>2002/08/01</h3>
Speex 0.6.0 has been released. This is a major release that contains many improvements and lots of bug-fixing. The post-filter that was causing problems throughout 0.5.x was replaced with a new perceptual enhancement system, which sounds better and consume much less CPU. Also many changes to Ogg encoder/decoder, including possibility to see the bit-rate being played/encoded. There is also a discontinuous transmission (DTX) mode. Last but not least, 0.6.0 now reports no error when being run with the valgrind memory debugger.
<h3>2002/07/26</h3>
Speex 0.5.2 is out and brings a number of improvements and bug fixes. First,
the search has been improved and it is now possible to choose the right
quality/encoding time tradeoff (--comp option). Is is also possible to pack
more that one frame in an Ogg packet (--nframes), reducing the overhead for
low bit-rates. Last but not least: there is now some documentation about
Speex!
<h3>2002/07/17</h3>
Version 0.5.1 is released. This release brings quality improvements at very
low bit-rate (5.7 kbps) and a new post-filter. VBR should also be a bit
better though there's still a lot to do. Most of the modes are bit-rate
compatible with 0.5.0, with the exception of the very low bit-rate (which is
sometimes used in VBR, so expect some glitches). The source (and probably
binary) compatibility with 0.5.0 is maintained.
<h3>2002/07/08</h3>
Speex 0.5.0 is out. The most important new feature is Varible Bit-Rate
(VBR). It can be enabled by using the --vbr option to speexenc. When
encoding in VBR, the --quality option can still be used. Note VBR
implementation in this release is experimental and still requires lots of
tuning.
<h3>2002/06/23</h3>
Speex 0.4.0 is here, adding many more bit-rates to both narrowband and wideband, as
well as the ability to change bit-rate dynamically from frame to frame. The
narrowband modes now range from 8 kbps to 18 kbps, while wideband range from
10 kbps to 28 kbps. There is also a "noise coding" mode at 2 kbps for
narrowband and 3 kbps for wideband. All this will lead to real Variable
Bit-Rate (VBR) in the future. Also, worth mentioning the codec latency has
been reduced from 40 ms to 30 ms (20 ms frames + 10 ms lookahead).
<h3>2002/06/12</h3>
Speex 0.3.0 has been released. There is now a new "low bit-rate" narrowband
mode for coding speech at 8 kbps. There's also support for big-endian
machines (untested, please report bugs). Speex files now have real header
containing information like bit-stream version (revents from playing an
incompatible bit-stream), sampling rate, bit-rate and user comments. On the
quality side, the post-filter has been improved and there has been more
codebook optimization. Note that this release breaks bit-stream
compatibility with previous releases.
<h3>2002/06/07</h3>
Speex 0.2.0 is out. This is a major release with lots of improvements and
bugfixes. First, the encoder and decoder can work directly from wav files
(mono only for now) and the decoder can play directly to soundcard. Also,
most of the codebooks have been re-trained in order to improve quality (but
this also breaks format compatibility with previous versions), while
slightly decreasing complexity. Speex is now able to encode both DTMF and
music (not as good as Vorbis of course) after bugs were fixed in the pitch
prediction and LSP quantization. Last but not the least, the perceptual
post-filter has been improved.
<h3>2002/06/04</h3>
Speex 0.1.2 is out. This adds a perceptual post-filter at the decoder to
(hopefully) increase quality. It can be enabled with the --pf option to
speexdec. The Speex format remains the same for both narrowband
and wideband.
<h3>2002/05/15</h3>
Speex 0.1.0 has been released. Speex now uses the Ogg bitstream (using
libogg). That means that there is now (limited) bitstream error
recovery. Also, the narrowband bit-rate has been reduced from 15.7 kbps to
15.1 kbps and the wideband bit-rate has been reduced from 31.3 kbps to 27.7
kbps. The quality remains roughly the same for both narrowband and
wideband. Once again, this breaks compatibility with previous versions.
<hr width="100%" size="2">
<div align="right"><a href="http://uk.eurorights.org/issues/cd/quick/"><img
border="0" width="160" height="40" src="badcd002.png"
alt="Say NO to corrupt audio discs" /></a>
<br>
<img src="http://sourceforge.net/sflogo.php?group_id=46651&amp;type=5" alt="SourceForge Logo">
<br>
<a href="mailto:jean-marc.valin@hermes.usherb.ca">Jean-Mrc Valin</a> <br>
$Date: 2002/08/16 06:24:19 $</div>
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