[Speex-dev] how to fix high freq noise?

Jason Hennigar jhennigar at pantelintl.com
Fri Jan 9 11:50:56 PST 2009

Hi Jean-Marc,

I just retested the speex audio with speex-svn-14525 and speex-svn-15540 
with the original Blackfin makefile configuration settings. The two 
tones are still present. The original setting are below.


In order to use these settings with the speex-svn-15540 a minor 
modification was required to the preprocess.c module. agc_level is not 
declared when fixed point is used.

< #ifndef FIXED_POINT
< #endif /* #ifndef FIXED_POINT */


Jason Hennigar wrote:
> Hi Jean-Marc,
> Thanks for the quick response! I am resending this mail hopefully in 
> plain text.
> The following three version have been tried and all of them have the 
> high frequency tones.
> speex-svn-14525
> speex-1.2rc
> speex-svn-15540
> I've isolated this down to the Speex encode/decode by sending silence 
> (i.e. all zeros) to the encoder and displaying the decoder output in 
> addition to recording the audio. The ALSA functionality that I am 
> using to receive and transmit audio is not introducing the problem as 
> it works correctly when I remove Speex. The problem occurs both on the 
> Blackfin 537 Stamp board with the AD1836 audio daughter card and with 
> our own 537 hardware.
> The build configuration settings that I am using are as follows:
>    --without-ogg
>    --without-ogg-libraries
>    --without-ogg-includes
>    --disable-oggtest
>    --enable-blackfin-asm
>    --enable-fixed-point
>    --disable-float-api
>    --disable-vbr
> Cheers!
> Jason
> Jean-Marc Valin wrote:
>> What version did you use. Some older releases had encoder-side issues
>> with some times, but that should be fixed now.
>>     Jean-Marc
>> Jason Hennigar a écrit :
>>> Hi Masakazu,
>>> I have reproduced the Speex high frequency noise issue on a Blackfin 
>>> 537 by sending 'silence' into the Speex fixed point encoder. By 
>>> recording the Speex decoder output and plotting the spectrum using 
>>> Audacity the following two frequencies.
>>> 1596Hz at -31.3dB
>>> 3200Hz at -48dB
>>> These two frequencies are present in both Narrow Band and Wide Band 
>>> modes. I've tried a number of different configurations and these two 
>>> frequencies are always present (quality set to 10 or default, the 
>>> complexity set to default, perceptual enhancement turned on or off). 
>>> I have not determined how to correct this problem but wanted to 
>>> provide additional information.
>>> Cheers!
>>> Jason
>>> _______________________________________________
>>> Speex-dev mailing list
>>> Speex-dev at xiph.org
>>> http://lists.xiph.org/mailman/listinfo/speex-dev

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