1 files changed, 79 insertions, 0 deletions
diff --git a/python/demos/demo_tempo_plot.py b/python/demos/demo_tempo_plot.py
new file mode 100755
index 0000000..48a6ccf
--- /dev/null
+++ b/python/demos/demo_tempo_plot.py
@@ -0,0 +1,79 @@
+#! /usr/bin/env python
+
+import sys
+from aubio import tempo, source
+
+win_s = 512                 # fft size
+hop_s = win_s // 2          # hop size
+
+if len(sys.argv) < 2:
+    print("Usage: %s <filename> [samplerate]" % sys.argv[0])
+    sys.exit(1)
+
+filename = sys.argv[1]
+
+samplerate = 0
+if len( sys.argv ) > 2: samplerate = int(sys.argv[2])
+
+s = source(filename, samplerate, hop_s)
+samplerate = s.samplerate
+o = tempo("default", win_s, hop_s, samplerate)
+
+# tempo detection delay, in samples
+# default to 4 blocks delay to catch up with
+delay = 4. * hop_s
+
+# list of beats, in samples
+beats = []
+
+# total number of frames read
+total_frames = 0
+while True:
+    samples, read = s()
+    is_beat = o(samples)
+    if is_beat:
+        this_beat = o.get_last_s()
+        beats.append(this_beat)
+    total_frames += read
+    if read < hop_s: break
+
+if len(beats) > 1:
+    # do plotting
+    from numpy import mean, median, diff
+    import matplotlib.pyplot as plt
+    bpms = 60./ diff(beats)
+    print('mean period: %.2fbpm, median: %.2fbpm' % (mean(bpms), median(bpms)))
+    print('plotting %s' % filename)
+    plt1 = plt.axes([0.1, 0.75, 0.8, 0.19])
+    plt2 = plt.axes([0.1, 0.1, 0.8, 0.65], sharex = plt1)
+    plt.rc('lines',linewidth='.8')
+    for stamp in beats: plt1.plot([stamp, stamp], [-1., 1.], '-r')
+    plt1.axis(xmin = 0., xmax = total_frames / float(samplerate) )
+    plt1.xaxis.set_visible(False)
+    plt1.yaxis.set_visible(False)
+
+    # plot actual periods
+    plt2.plot(beats[1:], bpms, '-', label = 'raw')
+
+    # plot moving median of 5 last periods
+    median_win_s = 5
+    bpms_median = [ median(bpms[i:i + median_win_s:1]) for i in range(len(bpms) - median_win_s ) ]
+    plt2.plot(beats[median_win_s+1:], bpms_median, '-', label = 'median of %d' % median_win_s)
+    # plot moving median of 10 last periods
+    median_win_s = 20
+    bpms_median = [ median(bpms[i:i + median_win_s:1]) for i in range(len(bpms) - median_win_s ) ]
+    plt2.plot(beats[median_win_s+1:], bpms_median, '-', label = 'median of %d' % median_win_s)
+
+    plt2.axis(ymin = min(bpms), ymax = max(bpms))
+    #plt2.axis(ymin = 40, ymax = 240)
+    plt.xlabel('time (mm:ss)')
+    plt.ylabel('beats per minute (bpm)')
+    plt2.set_xticklabels([ "%02d:%02d" % (t/60, t%60) for t in plt2.get_xticks()[:-1]], rotation = 50)
+
+    #plt.savefig('/tmp/t.png', dpi=200)
+    plt2.legend()
+    plt.show()
+
+else:
+    print('mean period: %.2fbpm, median: %.2fbpm' % (0, 0))
+    print('plotting %s' % filename)