[Speex-dev] VAD Questions

Larry Gadallah lgadallah at gmail.com
Thu Jun 7 13:55:48 PDT 2007

Hello all:

I am interested in using Speex for an application that streams audio
from a (noisy) source, so I am interested in VAD and DTX operation.
However, after browsing the archives of this list, I note that a
number of people have not been satisfied with the operation of the VAD
algorithm in Speex. This leads me to a few questions:

- Is there a reference somewhere (other than the source itself) that
explains how the latest VAD algorithm works?
- Is it possible to obtain the VAD status of a Speex stream
asynchronously? The current API seems to imply that some kind of
polling is required to determine the voice/non-voice status.
- Does the VAD algorithm implement syllabic/sonorant rate detection,
as has been implemented many times in analog circuitry, and is
described in this (and other) papers?
- Over what time period is VAD done? Is it done on a frame by frame
basis or over some longer period?

Thank you,
Larry Gadallah, VE6VQ/W7                          lgadallah AT gmail DOT com
PGP Sig: 616D 4E52 CF1F 3FEC FFFB  F11B 7DB9 C79A EA7E B25B

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