[Speex-dev] Problem encoding sine wave in 1.1.6 and somewhat in 1.0.4

Jared Whitby jwhitby at gmail.com
Thu Jan 13 11:19:06 PST 2005

Well I think a sinusoid shouldn't totally trash the encoder state, so
I still think theres a bug lurking around in there. The denoiser just
prevents it from ever making it to the encoder. Just from browsing
through the speex code and from what I've learned reading through the
mailing list, it looks like there are a few places where checks are in
place to prevent sinusoids from destabilizing the stream. Somehow this
particular sine wave is getting through the cracks I think. I actually
tried a couple of lower frequency samples and It didn't seem to cause
the problem I was having.

But, I seem to be in good shape with the filter in place... so just
figured I would share what i have learned.


On Thu, 13 Jan 2005 19:40:11 +0100, Claude Brisson <claude at renegat.net> wrote:
> On Thu, 2005-01-13 at 12:42 -0500, Jean-Marc Valin wrote:
> > Le jeudi 13 janvier 2005 à 10:59 -0500, Jared Whitby a écrit :
> > > Interestingly enough.. I started playing around with preprocessing
> > > options in 1.1.6 and happened upon the denoise filter
> > > (SPEEX_PREPROCESS_SET_DENOISE). When i run the test tone using that
> > > option it is completely filtered out and I just get (complete)
> > > silence. When the test tone is intermixed with regular voice I only
> > > get the voice. So while i still don't quite understand why the test
> > > tone dorks up the encoder, it looks like I have a way around it.
> >
> > Well, the denoiser is designed to remove any kind of stationary
> > background noise. You sinusoid fits that definition pretty well :-)
> >
> >       Jean-Marc
> The "Is is a bug? No, it's a feature" has just make another victim!
> Claude

jwhitby at gmail.com

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