Comparing audio files

Discussion in 'Perl Misc' started by kieran, Oct 8, 2008.

  1. kieran

    kieran Guest

    I am trying to compare two similar audio files (WAV). From what i have
    read i need to sample both audio files at certain frequencies and run
    these through a FFT and then compare the results. Can anyone advise me
    if this is the correct approach and also describe the steps i need to
    take to get to the stage where I can compare the files.
    kieran, Oct 8, 2008
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  2. You could try the ESP::pSI module.

    Jürgen Exner, Oct 8, 2008
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  3. kieran

    kieran Guest

    Hi Jue,
    thanks for your reply, i have searched for the module you mentiones in
    CPAN and Google but could not find it.
    Can you please send me a link.
    Best Regards,
    kieran, Oct 15, 2008
  4. kieran

    greymaus Guest

    The reply may, just may, be his attempt at humour. You can try the NSA!.
    greymaus, Oct 15, 2008
  5. Surely there's an Acme::ESP and Acme::pSI in CPAN?


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    RedGrittyBrick, Oct 15, 2008
  6. kieran

    Ted Zlatanov Guest

    Ted Zlatanov, Oct 15, 2008
  7. RedGrittyBrick, Oct 15, 2008
  8. kieran

    kieran Guest

    Hi Christian,
    Thanks for your reply, the approach you describe will certainly help,
    I have requested a trial version of Octave so I will begin using that
    for protoyyping once I get access.

    A couple of things you might be able to help me with, I have been
    looking for some modules to use for downsampling, filtering etc... The
    module I found for resampling audio called Audio::Mad::Resample would
    not install on my machine, i got some errors that i could not resolve.
    Are there any modules you can recomend for down/up sampling?
    Also for creating a low-pass filter i have been looking at PDL::Audio,
    there are many types of filter available in this module, I am not sure
    which is best for low-pass filters.
    kieran, Oct 22, 2008
  9. kieran

    kieran Guest

    I have done some of the work in prototyping the wav file comparison in
    MATLAB and I have begun translating this into perl. I am experiencing
    some problems when I read the data from the wave file in perl, the
    values I am getting seem very large and seem to be 3,000(aprox.) times
    larger than the values i get when i imported the wav file data into
    Matlab. When I graph both sets of values the resulting graphs look the
    same as the wave form.
    In matlab i am using the wavread function to read the samples from my
    wav file. I get 49617 samples of very low numbers, lots of zero values
    and plenty of very low and negative values. I have followed a few
    tutorials in Matlab and these reading look correct.
    However when i attempt to do the same in perl i get the smae ammount
    of samples but the numbers are very large and with few if any zero
    readings. I have been uing the Audio::Analyzer Audio::Wav::Read
    Can you explain why I am getting such a large difference between
    Matlab nad perl? I would expect the results to match.
    If you require any more information please let me know.
    kieran, Nov 11, 2008
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