[Speex-dev] how to fix high freq noise?
jhennigar at pantelintl.com
Thu Jan 8 07:47:00 PST 2009
Thanks for the quick response! I am resending this mail hopefully in
The following three version have been tried and all of them have the
high frequency tones.
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
The build configuration settings that I am using are as follows:
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.
> 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.
>> Speex-dev mailing list
>> Speex-dev at xiph.org
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