[Clam-devel] MFCC Loops

paul simmons pauls631 at gmail.com
Mon Sep 7 14:27:11 PDT 2009


Hi,
I think the problem is about my SpectralAnalysis config. Just to
clarify; I send an audio as the code below, at each while() iteration,
it reads a chunk of audio (in size of Audio.SetSize()) and returns
just one spectrum, melspectrum and mfcc vector (ok, let's put
overlapping for a moment). But if you say SpectralAnalysis handles
everything (and I configure right), I think I should get an array of
spectrum (and others) vector according to the HopSize right? What is
my mistake here?





On Tue, Sep 8, 2009 at 12:01 AM, Xavier Amatriain<xavier at amatriain.net> wrote:
> I don't think there is a simple example of this. However, if I remember
> right, there are two ways to do the loop if you want to have overlapping
> windows or frames:
>
> 1) Read the whole audio from the audio file into a CLAM::Audio and manage
> the "chunk" you send to the SpectralAnalysis Do by advancing your read
> pointer by "hopsize" (which, if overlapping, will be less than windowSize)
>
> 2) Use ports and let them manage this for you. This is what you can see if
> you analyze the code in SMSAnalysisCore.cxx
>
> http://clam-project.org/doc/CLAM-doxygen/SMSAnalysisCore_8cxx-source.html
>
> If you don't need overlap, SpectralAnalysis will take care of everything
> (windowing, etc...) as long as you configure the parameters right so you
> don't need to worry about 1 or 2.
>
> X
>
> paul simmons wrote:
>>
>> well, let me change the question then. is there a "code" sample for
>> doing spectral analysis with overlapping windows (ie using windowsize
>> and hopsize parameters)?
>>
>>
>>
>> On Mon, Sep 7, 2009 at 8:24 PM, Pau Arumí<pau.arumi at barcelonamedia.org>
>> wrote:
>>
>>>
>>> Hi Paul,
>>> I didn't understand exactly where the problem is.
>>> (However I think the most qualified to answer you is David Garcia who is
>>> currently on holidays. He'll be back in a week or two.)
>>>
>>> Cheers
>>> P
>>>
>>> El dl 07 de 09 de 2009 a les 16:54 +0200, en/na paul simmons va
>>> escriure:
>>>
>>>>
>>>> Hi,
>>>> I am trying to do MFCC extraction. As far as I get; the steps are
>>>>
>>>> Read an "Audio"
>>>> Run "SpectralAnalysis" on output of "Audio"
>>>> Run "MelFilterBank" on output of "SpectralAnalysis"
>>>> Run "CepstralTransform" on output of "MelFilterBank"
>>>>
>>>> right?
>>>>
>>>> If so; I cannot understand where to do looping, for example if I do:
>>>>
>>>>    while(mReader.Do(audio))
>>>>    {
>>>>        spectralAnalysis.Do(audio, spectrum);
>>>>        melFilterBank.Do(spectrum, melSpectrum);
>>>>        cepstralTransform.Do(melSpectrum, melCepstrum);
>>>>
>>>>        CLAM::XMLStorage::Dump(audio,"Audio",a);
>>>>        CLAM::XMLStorage::Dump(spectrum, "Spectrum",s);
>>>>        CLAM::XMLStorage::Dump(melSpectrum, "MelSpectrum",m);
>>>>        CLAM::XMLStorage::Dump(melCepstrum, "MelCepstrum",n);
>>>>    }
>>>>
>>>> it applies mfcc to each read audio patch (mentioned by Audio.SetSize)
>>>> and got one MFCC feature vector. But I cannot understand how
>>>> WindowSize or HopSize is applied in this fashion. Because since Audio
>>>> is read in non-overlapping windows with mReader.Do(), overlapped
>>>> windows are run only for current audio part
>>>>
>>>> I think there must be another , more correct way to get overlapping
>>>> windows continuesly in whole audio, but cannot find it. Any ideas?
>>>>
>>>> Thanks...
>>>>
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>>
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