Simplify

spectrogram.py

@@ -3,31 +3,26 @@ import numpy as np
 import matplotlib.image as mpimg
 import wave
 from array import array
-from progressbar import ProgressBar
-
-def write_column(output_file, pixels, rescale=.1):
-    """ Write a single column of sound """
-    curve = np.fft.ifft(pixels, len(pixels)*2).real
-    curve = np.array((curve-np.average(curve))*rescale, dtype=int)
-    data = array("h", curve).tostring()
-    output_file.writeframes(data)
 
 
 def make_wav(image_filename):
     """ Make a WAV file having a spectrogram resembling an image """
+    # Load image
     image = mpimg.imread(image_filename)
     image = np.sum(image, axis = 2).T[:, ::-1]
-    image = image**2
+    image = image**3 # ???
+    w, h = image.shape
+
+    # Fourier transform, normalize, remove DC bias
+    data = np.fft.irfft(image, h*2, axis=1).reshape((w*h*2))
+    data -= np.average(data)
+    data *= (2**15.-1)/np.amax(data)
+    data = array("h", np.int_(data)).tostring()
 
+    # Write to disk
     output_file = wave.open(image_filename+".wav", "w")
     output_file.setparams((1, 2, 44100, 0, "NONE", "not compressed"))
-
-    pb = ProgressBar().start()
-    n = float(len(image))
-    for index, column in enumerate(image):
-        write_column(output_file, column)
-        pb.update(index*100/n)
-
+    output_file.writeframes(data)
     output_file.close()
     print "Wrote %s.wav" % image_filename