Volume

Volume/Volume.py

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+import math
+import numpy as np
+
+# method 1: absSum
+def calVolume(waveData, frameSize, overLap):
+    wlen = len(waveData)
+    step = frameSize - overLap
+    frameNum = int(math.ceil(wlen*1.0/step))
+    volume = np.zeros((frameNum,1))
+    for i in range(frameNum):
+        curFrame = waveData[np.arange(i*step,min(i*step+frameSize,wlen))]
+        #curFrame = curFrame - np.median(curFrame) # False
+        curFrame = curFrame - np.mean(curFrame) # zero-justified
+        volume[i] = np.sum(np.abs(curFrame))
+    return volume
+
+# method 2: log10 of square sum
+def calVolumeDB(waveData, frameSize, overLap):
+    wlen = len(waveData)
+    step = frameSize - overLap
+    frameNum = int(math.ceil(wlen*1.0/step))
+    volume = np.zeros((frameNum,1))
+    for i in range(frameNum):
+        curFrame = waveData[np.arange(i*step,min(i*step+frameSize,wlen))]
+        curFrame = curFrame - np.mean(curFrame) # zero-justified
+        volume[i] = 10*np.log10(np.sum(curFrame*curFrame))
+    return volume

Volume/VolumeTest.py

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+import wave
+import pylab as pl
+import numpy as np
+import Volume as vp
+
+# ============ test the algorithm =============
+# read wave file and get parameters.
+fw = wave.open('../sounds/aeiou.wav','rb')
+params = fw.getparams()
+print(params)
+nchannels, sampwidth, framerate, nframes = params[:4]
+strData = fw.readframes(nframes)
+waveData = np.fromstring(strData, dtype=np.int16)
+waveData = waveData*1.0/max(abs(waveData))  # normalization
+fw.close()
+
+# calculate volume
+frameSize = 256
+overLap = 128
+volume11 = vp.calVolume(waveData,frameSize,overLap)
+volume12 = vp.calVolumeDB(waveData,frameSize,overLap)
+
+# plot the wave
+time = np.arange(0, nframes)*(1.0/framerate)
+time2 = np.arange(0, len(volume11))*(frameSize-overLap)*1.0/framerate
+pl.subplot(311)
+pl.plot(time, waveData)
+pl.ylabel("Amplitude")
+
+pl.subplot(312)
+pl.plot(time2, volume11)
+pl.ylabel("absSum")
+
+pl.subplot(313)
+pl.plot(time2, volume12, c="g")
+pl.ylabel("Decibel(dB)")
+pl.xlabel("time (seconds)")
+pl.show()