Decoding wav files for FFT

[kieran]

Hello,
I have been working on an audio comparison project which involves
running an FFT on some .wav files. The first thing I need to do id get
the wav information into my perl program so that I can run the FFT on
the data.
I used Matlab to import the wav file, which automaticall extracted the
samples from the wavfile.
I am looking to do the same in perl but the results I get when I try
to pull out the sampels from the wav file are very different to what i
am seeing in Matlab.
I have used Audio::Wav read() and Audio::Analyzer chunk->pcm
The results I am getting back from Audio::Wav read seem very large
(-80, -69, -73, 84, 66, etc...) with very few zero values, wheres as
with Matlab the results I am gettting back are as follows (0
-3.05175781250000e-05, -3.05175781250000e-05, 3.05175781250000e-05,
-3.05175781250000e-05,
-3.05175781250000e-05, etc...)

Any idea why I am getting such different results?
Any help greatly appreciated,
kieran

 

[smallpond]

Hello,
I have been working on an audio comparison project which involves
running an FFT on some .wav files. The first thing I need to do id get
the wav information into my perl program so that I can run the FFT on
the data.
I used Matlab to import the wav file, which automaticall extracted the
samples from the wavfile.
I am looking to do the same in perl but the results I get when I try
to pull out the sampels from the wav file are very different to what i
am seeing in Matlab.
I have used Audio::Wav read() and Audio::Analyzer chunk->pcm
The results I am getting back from Audio::Wav read seem very large
(-80, -69, -73, 84, 66, etc...) with very few zero values, wheres as
with Matlab the results I am gettting back are as follows (0
-3.05175781250000e-05, -3.05175781250000e-05, 3.05175781250000e-05,
-3.05175781250000e-05,
-3.05175781250000e-05, etc...)

Any idea why I am getting such different results?
Any help greatly appreciated,
kieran

Which scaler are you using?

 

[kieran]

Which scaler are you using?

Hi Smallpond,
I didn't specify a scalar, Im also new to perl so I'm not sure if this
is something I'm missing.
K

 

[smallpond]

Hi Smallpond,
I didn't specify a scalar, Im also new to perl so I'm not sure if this
is something I'm missing.
K

scaler, not scalar. See:
http://search.cpan.org/~triddle/Audio-Analyzer-0.1/lib/Audio/Analyzer.pm#SCALER_CLASSES