changeset 3:8af0cef242b8

added two drum audio files and some block by block processing and plottig examples

Binary file drums_mono.wav has changed

Binary file drums_stereo.wav has changed

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dsp-block-by-block.py	Wed Sep 12 21:38:54 2012 +0100
@@ -0,0 +1,41 @@
+import numpy as np
+from scikits.audiolab import wavread
+
+#################################################
+############ EXTRACT AUDIO FROM FILE ############
+#################################################
+
+x, fs, enc = wavread("viola.wav")
+
+
+#################################################
+#### CALCULATE RMS OF EACH AUDIO BLOCK ####
+#################################################
+
+hop_size = 2048                             # set hop size
+frame_size = 4096                           # set frame size
+frame = np.zeros(frame_size)                # initialise frame with zeros
+window = np.hanning(frame_size)             # create window of the same length as the hop size
+
+# create empty numpy array to hold our 
+rms = np.array([])
+
+# run through signal frame by frame 
+for n in range(0,x.size-hop_size,hop_size):
+    
+    # extract a segment of length hop_size
+    buffer = x[n:n+hop_size]                               
+    
+    # add new segment to frame, shifting back samples of frame
+    frame = np.append(frame[hop_size:frame_size],buffer)  
+    
+    # calculate RMS
+    rms_val = np.sqrt(np.power(frame,2).mean())
+    
+    # add amplitude to our numpy array
+    rms = np.append(rms,rms_val)
+
+print rms
+    
+                                   
+ 
\ No newline at end of file

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/plotting.py	Wed Sep 12 21:38:54 2012 +0100
@@ -0,0 +1,48 @@
+import numpy as np
+from scikits.audiolab import wavread
+from matplotlib import pylab as plt
+
+#################################################
+############ EXTRACT AUDIO FROM FILE ############
+#################################################
+
+x, fs, enc = wavread("drums_mono.wav")
+
+
+#################################################
+#### CALCULATE RMS OF EACH AUDIO BLOCK ####
+#################################################
+
+hop_size = 1024                              # set hop size
+frame_size = hop_size*2                     # set frame size
+frame = np.zeros(frame_size)                # initialise frame with zeros
+window = np.hanning(frame_size)             # create window of the same length as the hop size
+
+# create empty numpy array to hold our 
+rms = np.array([])
+
+# run through signal frame by frame 
+for n in range(0,x.size-hop_size,hop_size):
+    
+    # extract a segment of length hop_size
+    buffer = x[n:n+hop_size]                               
+    
+    # add new segment to frame, shifting back samples of frame
+    frame = np.append(frame[hop_size:frame_size],buffer)  
+    
+    # calculate RMS
+    rms_val = np.sqrt(np.power(frame,2).mean())
+    
+    # add amplitude to our numpy array
+    rms = np.append(rms,rms_val)
+
+print rms
+
+
+plt.plot(rms)
+plt.title("RMS")
+plt.xlabel("time")
+plt.ylabel("value")
+plt.show()
+    
+