Revision 6:fd0f9d0615b2 8-dsp-delay.py

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8-dsp-delay.py
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import numpy as np
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from scikits.audiolab import wavread
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from scikits.audiolab import Format
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from scikits.audiolab import Sndfile
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from scikits.audiolab import Format
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#################################################


  		




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######## CREATING A SOUND FILE INSTANCE #########


  		




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#################################################


  		




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# create Sndfile instance with our example audio file


  		




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f = Sndfile('viola.wav', 'r')


  		




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#################################################


  		




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######## EXTRACTING AUDIO FILE META-DATA ########


  		




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#################################################


  		




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# extract and print sample rate


  		




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fs = f.samplerate


  		




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print "sample rate: ",fs


  		




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# extract and print the number of channels


  		




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nc = f.channels


  		




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print "number of channels: ",nc


  		




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# extract the number of samples


  		




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nsamples = f.nframes


  		




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#################################################


  		




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######## READ AUDIO SAMPLES FROM THE FILE #######


  		




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#################################################


  		




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# we can read audio samples using the read_frame method


  		




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data = f.read_frames(nsamples)


  		




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# extract audio from file


  		




  
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samples, fs, enc = wavread('viola.wav')  


  		




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#################################################


  		




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########## APPLY A DELAY TO THE SAMPLES #########


  		




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alpha = 0.75


  		




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# create an empty array for the output


  		




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out = np.zeros(data.size)


  		




  
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out = np.zeros(samples.size)


  		




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# for every sample in the array


  		




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for i in range(data.size):


  		




  
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for i in range(samples.size):


  		




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    # if we are safe to apply the delay without negative indexing


  		




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    if (i >= delay):


  		




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        out[i] = data[i] + data[i-delay]*alpha


  		




  
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        out[i] = samples[i] + samples[i-delay]*alpha


  		




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    else:


  		




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        out[i] = data[i] # hacky


  		




  
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        out[i] = samples[i] # hacky


  		




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#################################################


  		












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