[SciPy-dev] talkbox scikit

Georg Holzmann grh@mur...
Sat Feb 28 06:50:47 CST 2009


Hallo David !

I want to contribute some code to the talkbox scikit and have some 
questions.

- First, is this scikit also for audio signal processing / audio (music) 
feature extraction, or mainly for speech only ?

- Second, I have implemented some (random) code for audio signal 
processing which IMHO would be nice to have in a scikit:

* Implementation of a Generalized Cross Correlation (GCC) with various 
pre-whitening filters.
(after "The Generalized Correlation Method for Estimation of Time Delay" 
by Charles Knapp and Clifford Carter, programmed with looking at the 
matlab GCC implementation by Davide Renzi)
this function is used for robustly determine the time delay between two 
real signals

* Equivalent Rectangular Bandwidth Filter Coefficients for biquad IIR 
Filters.
(implemented after "An Efficient Implementation of the 
Patterson-Holdsworth Auditory Filter Bank" by Malcolm Slaney)

* Filter coefficients for a bank of Gammatone filters.
(implemented after "An Efficient Implementation of the
Patterson-Holdsworth Auditory Filter Bank" by Malcolm Slaney)
Implementation also with multiple biquad filters, to avoid numerical 
unstabilities.

* Common filter parameters for audio biquad IIR filters (after "Cookbook 
formulae for audio EQ biquad filter coefficients", 
http://www.musicdsp.org/files/Audio-EQ-Cookbook.txt)

* Conversion of linear IIR filter parameters to a minimum phase filter 
with the same amplitude response.

* MFCC feature extraction (but I have seen that you already have 
implemented mfccs...)

* I plan to implement more audio/music feature extraction methods in 
near future (chroma features, beat features, beat-synchronous features ...)


- OK, would this be suited for talkbox ? If yes, are there any guidlines 
how to contribute (I will adapt the code to your scikit style, writing 
more tests and docs) - I mean, should I just send you the code by mail ?

- In which categories should I put all these ? So I propose all the 
filter parameter calculations in talkbox/fbanks/, feature extraction 
methods of course into talkbox/features/ and the generalized cross 
correlation maybe into talkbox/tools/correlations.py, or maybe in a 
seperate file ... ?

- And last but not least, is this the right mailing list for such 
discussions ;) ? Or are there any special lists for scikits ?


OK, thanks for any feedback !
LG
Georg


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