The Speex project
aims to build an open-source (LGPL) patent-free voice codec. Unlike
other codecs like MP3 and Ogg Vorbis, 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.
If you are interested in participating to the project, contact us at
speex-devel@lists.sourceforge.net or
join our mailing list. 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.
Download
You can download Speex from
here.
Documentation
Speex Programming Guide
Speex API (generated by Doc++)
Samples
You can listen to samples encoded with Speex here
News
2002/06/07
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.
2002/06/04
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.
2002/05/15
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.