1 files changed, 56 insertions, 0 deletions
diff --git a/python/demos/demo_waveform_plot.py b/python/demos/demo_waveform_plot.py
new file mode 100755
index 0000000..5434223
--- /dev/null
+++ b/python/demos/demo_waveform_plot.py
@@ -0,0 +1,56 @@
+#! /usr/bin/env python
+
+import sys
+from aubio import source
+from numpy import zeros, hstack
+
+def get_waveform_plot(filename, samplerate = 0, block_size = 4096, ax = None, downsample = 2**4):
+    import matplotlib.pyplot as plt
+    if not ax:
+        fig = plt.figure()
+        ax = fig.add_subplot(111)
+    hop_s = block_size
+
+    allsamples_max = zeros(0,)
+    downsample = downsample  # to plot n samples / hop_s
+
+    a = source(filename, samplerate, hop_s)            # source file
+    if samplerate == 0: samplerate = a.samplerate
+
+    total_frames = 0
+    while True:
+        samples, read = a()
+        # keep some data to plot it later
+        new_maxes = (abs(samples.reshape(hop_s//downsample, downsample))).max(axis=0)
+        allsamples_max = hstack([allsamples_max, new_maxes])
+        total_frames += read
+        if read < hop_s: break
+    allsamples_max = (allsamples_max > 0) * allsamples_max
+    allsamples_max_times = [ ( float (t) / downsample ) * hop_s for t in range(len(allsamples_max)) ]
+
+    ax.plot(allsamples_max_times,  allsamples_max, '-b')
+    ax.plot(allsamples_max_times, -allsamples_max, '-b')
+    ax.axis(xmin = allsamples_max_times[0], xmax = allsamples_max_times[-1])
+
+    set_xlabels_sample2time(ax, allsamples_max_times[-1], samplerate)
+    return ax
+
+def set_xlabels_sample2time(ax, latest_sample, samplerate):
+    ax.axis(xmin = 0, xmax = latest_sample)
+    if latest_sample / float(samplerate) > 60:
+        ax.set_xlabel('time (mm:ss)')
+        ax.set_xticklabels([ "%02d:%02d" % (t/float(samplerate)/60, (t/float(samplerate))%60) for t in ax.get_xticks()[:-1]], rotation = 50)
+    else:
+        ax.set_xlabel('time (ss.mm)')
+        ax.set_xticklabels([ "%02d.%02d" % (t/float(samplerate), 100*((t/float(samplerate))%1) ) for t in ax.get_xticks()[:-1]], rotation = 50)
+
+
+if __name__ == '__main__':
+    import matplotlib.pyplot as plt
+    if len(sys.argv) < 2:
+        print("Usage: %s <filename>" % sys.argv[0])
+    else:
+        for soundfile in sys.argv[1:]:
+            get_waveform_plot(soundfile)
+            # display graph
+            plt.show()