[CLAM] MFCC with ClamExtractorExample

[David García Garzón]

On Dimecres 23 Gener 2008, vincenzo.dimattia wrote:
> Dear all,
> I am Vincenzo Dimattia, I am developing my final project, an automatic
> segmentation system.I am using the programm ClamExtractorExample for the
> extraction of the audio descriptors . I would like to know which are the
> parameters that this program uses to calculate the MFCC and how  this
> descriptor are stored in the pool document, is it a matrix which have
> dimension Frame x MFCC coefficients? I have read the doxygen documentation
> but i'm not  able to understand which parameters the programm use to
> calculate the MFCC descriptor. Thank you,
> Vincenzo Dimattia

Attributes can easily extracted from a pool using any XPath library to query 
an XPath expression such as:
	//ScopePool[@name='MyScope']/AttributePool[@name='MyAttibute']
Where MyScope::MyAttribute is the attribute to extract.

MFCCs are stored as Frame::MelFrequencyCepstrumCoefficients. It consists on a 
string of numbers containing all the coefficients for the first frame, then 
all the coefficients of the second frame and so on. 

//ScopePool[@name='MyScope']/AttributePool[@name='MyAttibute']/@size tells you 
the number of coefficients for each frame (20).

Analysis parameters are hardcoded into the source code of the example. It was 
an example for testing purposes so no text file configuration is provided. 
Here comes some config numbers:

Frames centers are defined as in the Song::Frames attribute (a first center 
and a gap).

FFTAnalysis:
	FrameSize: 1023
	SpectrumBins: 513
MelFreqFilterBank:
	NumBands: 20
	LowCutOff:  0 Hz
	HighCutOff:  11025 Hz
CepstralTransform:
	NumCoefficients: 20
	
	



-- 
David García Garzón
(Work) dgarcia at iua dot upf anotherdot es
http://www.iua.upf.edu/~dgarcia
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