[speex-dev] Beta 4 is out!

Jean-Marc Valin jean-marc.valin at hermes.usherb.ca
Fri Dec 20 13:28:23 PST 2002


I've just released beta4, which will hopefully be the last beta before
starting release candidates. There are a number of quality improvements
and a some new features. First, the quality of variable bit-rate (VBR)
has been greatly improved, mostly for wideband. Also, some improvements
were made to the packet-loss concealment code in order to reduce
artifacts caused by lost packets. There has been improvements to the
2.15 kbps mode, which now sounds a bit better. The last quality
improvement is in the perceptual enhancement which is now good enough to
be enabled by default in speexdec (but not by default in libspeex for

One of the new features in this release is a VAD (Voice Activity
Detection) mode that allows to save bit-rate when there's no speech even
without VBR enabled. This VAD comes with DTX (Discontinuous
Transmission) that allow to completely stop transmitting when the noise
is constant (in which case, comfort noise generation is turned on). The
last new feature in this release is an ABR (Average Bit-Rate) option,
which uses VBR with a quality that's adjusted to meet a certain target
(average) bit-rate.

As usual, you can download it from the site: http://www.speex.org . I've
also updated the samples page for beta4. Checkout Speex at 4 kbps VBR!



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