python/demos/demo_mfcc.py: add options to plot first and second derivatives, and...

diff --git a/python/demos/demo_mfcc.py b/python/demos/demo_mfcc.py
index dfbd7ed..5a33d15 100755 (executable)
--- a/python/demos/demo_mfcc.py
+++ b/python/demos/demo_mfcc.py
@@ -2,20 +2,27 @@
 
 import sys
 from aubio import source, pvoc, mfcc
-from numpy import vstack, zeros
+from numpy import vstack, zeros, diff
 
-win_s = 512                 # fft size
-hop_s = win_s // 4          # hop size
 n_filters = 40              # must be 40 for mfcc
 n_coeffs = 13
-samplerate = 44100
 
 if len(sys.argv) < 2:
-    print("Usage: %s <source_filename>" % sys.argv[0])
+    print("Usage: %s <source_filename> [samplerate] [win_s] [hop_s] [mode]" % sys.argv[0])
+    print("  where [mode] can be 'delta' or 'ddelta' for first and second derivatives")
     sys.exit(1)
 
 source_filename = sys.argv[1]
 
+if len(sys.argv) > 2: samplerate = int(sys.argv[2])
+else: samplerate = 0
+if len(sys.argv) > 3: win_s = int(sys.argv[3])
+else: win_s = 512
+if len(sys.argv) > 4: hop_s = int(sys.argv[4])
+else: hop_s = win_s // 4
+if len(sys.argv) > 5: mode = sys.argv[5]
+else: mode = "default"
+
 samplerate = 0
 if len( sys.argv ) > 2: samplerate = int(sys.argv[2])
 
@@ -48,18 +55,28 @@ get_waveform_plot( source_filename, samplerate, block_size = hop_s, ax = wave)
 wave.xaxis.set_visible(False)
 wave.yaxis.set_visible(False)
 
+# compute first and second derivatives
+if mode in ["delta", "ddelta"]:
+    mfccs = diff(mfccs, axis = 0)
+if mode == "ddelta":
+    mfccs = diff(mfccs, axis = 0)
+
 all_times = arange(mfccs.shape[0]) * hop_s
 n_coeffs = mfccs.shape[1]
 for i in range(n_coeffs):
     ax = plt.axes ( [0.1, 0.75 - ((i+1) * 0.65 / n_coeffs),  0.8, 0.65 / n_coeffs], sharex = wave )
     ax.xaxis.set_visible(False)
-    ax.yaxis.set_visible(False)
+    ax.set_yticks([])
+    ax.set_ylabel('%d' % i)
     ax.plot(all_times, mfccs.T[i])
 
 # add time to the last axis
-set_xlabels_sample2time( ax, frames_read, samplerate) 
+set_xlabels_sample2time( ax, frames_read, samplerate)
 
 #plt.ylabel('spectral descriptor value')
 ax.xaxis.set_visible(True)
-wave.set_title('MFCC for %s' % source_filename)
+title = 'MFCC for %s' % source_filename
+if mode == "delta": title = mode + " " + title
+elif mode == "ddelta": title = "double-delta" + " " + title
+wave.set_title(title)
 plt.show()