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commit ec0dac976e890c18fb50340de1d1d8fc1f83174e 0 parents
Nasca Octavian PAUL authored
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  1. +5 −0 README
  2. +149 −0 paulstretch_stereo.py
5 README
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+This is Paulstretch , Python version
+by Nasca Octavian PAUL, Targu Mures, Romania
+
+Requirements: Numpy, Scipy
+
149 paulstretch_stereo.py
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+#!/usr/bin/env python
+#
+# Paul's Extreme Sound Stretch (Paulstretch) - Python version
+#
+# by Nasca Octavian PAUL, Targu Mures, Romania
+#
+# http://hypermammut.sourceforge.net/paulstretch/
+#
+#
+
+
+import sys
+from numpy import *
+import scipy.io.wavfile
+import wave
+from optparse import OptionParser
+
+def load_wav(filename):
+ try:
+ wavedata=scipy.io.wavfile.read(filename)
+ samplerate=int(wavedata[0])
+ smp=wavedata[1]*(1.0/32768.0)
+ smp=smp.transpose()
+ if len(smp.shape)==1: #convert to stereo
+ smp=tile(smp,(2,1))
+ return (samplerate,smp)
+ except:
+ print "Error loading wav: "+filename
+ return None
+
+
+
+def optimize_windowsize(n):
+ orig_n=n
+ while True:
+ n=orig_n
+ while (n%2)==0:
+ n/=2
+ while (n%3)==0:
+ n/=3
+ while (n%5)==0:
+ n/=5
+
+ if n<2:
+ break
+ orig_n+=1
+ return orig_n
+
+def paulstretch(samplerate,smp,stretch,windowsize_seconds,outfilename):
+ nchannels=smp.shape[0]
+
+ outfile=wave.open(outfilename,"wb")
+ outfile.setsampwidth(2)
+ outfile.setframerate(samplerate)
+ outfile.setnchannels(nchannels)
+
+ #make sure that windowsize is even and larger than 16
+ windowsize=int(windowsize_seconds*samplerate)
+ if windowsize<16:
+ windowsize=16
+ windowsize=optimize_windowsize(windowsize)
+ windowsize=int(windowsize/2)*2
+ half_windowsize=int(windowsize/2)
+
+ #correct the end of the smp
+ nsamples=smp.shape[1]
+ end_size=int(samplerate*0.05)
+ if end_size<16:
+ end_size=16
+
+ smp[:,nsamples-end_size:nsamples]*=linspace(1,0,end_size)
+
+
+ #compute the displacement inside the input file
+ start_pos=0.0
+ displace_pos=(windowsize*0.5)/stretch
+
+ #create Hann window
+ window=0.5-cos(arange(windowsize,dtype='float')*2.0*pi/(windowsize-1))*0.5
+
+ old_windowed_buf=zeros((2,windowsize))
+ hinv_sqrt2=(1+sqrt(0.5))*0.5
+ hinv_buf=(hinv_sqrt2-(1.0-hinv_sqrt2)*cos(arange(half_windowsize,dtype='float')*2.0*pi/half_windowsize))/hinv_sqrt2
+
+ while True:
+ #get the windowed buffer
+ istart_pos=int(floor(start_pos))
+ buf=smp[:,istart_pos:istart_pos+windowsize]
+ if buf.shape[1]<windowsize:
+ buf=append(buf,zeros((2,windowsize-buf.shape[1])),1)
+ buf=buf*window
+
+ #get the amplitudes of the frequency components and discard the phases
+ freqs=abs(fft.rfft(buf))
+
+ #randomize the phases by multiplication with a random complex number with modulus=1
+ ph=random.uniform(0,2*pi,(nchannels,freqs.shape[1]))*1j
+ freqs=freqs*exp(ph)
+
+ #do the inverse FFT
+ buf=fft.irfft(freqs)
+
+ #window again the output buffer
+ buf*=window
+
+ #overlap-add the output
+ output=buf[:,0:half_windowsize]+old_windowed_buf[:,half_windowsize:windowsize]
+ old_windowed_buf=buf
+
+ #remove the resulted amplitude modulation
+ output*=hinv_buf
+
+ #clamp the values to -1..1
+ output[output>1.0]=1.0
+ output[output<-1.0]=-1.0
+
+ #write the output to wav file
+ outfile.writeframes(int16(output.ravel(1)*32767.0).tostring())
+
+ start_pos+=displace_pos
+ if start_pos>=nsamples:
+ print "100 %"
+ break
+ print "%d %% \r" % int(100.0*start_pos/nsamples),
+ sys.stdout.flush()
+
+ outfile.close()
+
+########################################
+print "Paul's Extreme Sound Stretch (Paulstretch) - Python version 20110219"
+print "by Nasca Octavian PAUL, Targu Mures, Romania\n"
+parser = OptionParser(usage="usage: %prog [options] input_wav output_wav")
+parser.add_option("-s", "--stretch", dest="stretch",help="stretch amount (1.0 = no stretch)",type="float",default=8.0)
+parser.add_option("-w", "--window_size", dest="window_size",help="window size (seconds)",type="float",default=0.25)
+(options, args) = parser.parse_args()
+
+
+if (len(args)<2) or (options.stretch<=0.0) or (options.window_size<=0.001):
+ print "Error in command line parameters. Run this program with --help for help."
+ sys.exit(1)
+
+print "stretch amount =",options.stretch
+print "window size =",options.window_size,"seconds"
+(samplerate,smp)=load_wav(args[0])
+
+paulstretch(samplerate,smp,options.stretch,options.window_size,args[1])
+
+
+
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