[Speex-dev] white noise problem when using -DFIXED_POINT

Jean-Marc Valin jean-marc.valin at usherbrooke.ca
Tue Sep 14 22:50:24 PDT 2004

Hi Owen,

I have little time right now to look at the details, but it would help
if you could test with all 1.1.x versions and see when the problem
appeared. Also, compile with --enable-fixed-point-debug so messages will
be printed in case of overflows.


P.S. Please also post the original file.

On mar, 2004-09-14 at 22:42 -0700, wrote:
> Jean-Marc Valin wrote:
> > On mar, 2004-09-14 at 16:31 -0700, wrote:
> > 
> >>Hi there.  We're trying to build a speex decoder for Palm OS (i.e. ARM7).
> >>
> >>No major problems porting thus far, but when compiling the speex modules with -DFIXED_POINT all the silent parts of the output are replaced with what sounds like high-power white noise.  The spoken parts sound great, but all the silent parts in between speaking just sounds like white noise.
> >>
> >>We're using speex 1.1.6, and current libogg sources pulled down from subversion.
> > 
> > 
> > It's difficult to say with only that info. Have you tried the same file
> > on an x86 (with and without FIXED_POINT) and comparing the results. If
> > you still can't find the problem, please post the file somewhere (along
> > with the encoded version) and I'll have a look at it. Oh, and are you
> > using speexenc/speexdec or you own encoder and decoder?
> > 
> > 	Jean-Marc
> Jean-Marc,
> Thanks for the quick reply, and sorry for eliding some of the details.  Our test builds thus far have indeed been on x86.  I reproduced the white noise condition described above using unmodified speexdec from speex 1.1.6, configured with --enable-fixed-point.  The output sounds okay when configured without fixed point support.
> As I mentioned, we're using speex 1.1.6, current svn libogg, and gcc 2.95.4.
> Here is one of the files that seems to exhibit the problem:
> http://owen.theemrys.com/speex/0102.spx
> Thanks in advance for any information.  I've spent the last few hours combing the list archives, but nothing seems to stand out.
> Best regards,
> Owen

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