demo_beats_and_tempo.py: improved beat demo

diff --git a/interfaces/python/demo_beat.py b/interfaces/python/demo_beat.py
deleted file mode 100644 (file)
index 0737492..0000000
--- a/interfaces/python/demo_beat.py
+++ /dev/null
@@ -1,27 +0,0 @@
-#! /usr/bin/python
-
-import sys
-from os.path import splitext, basename
-from aubio import tempo 
-from aubioinput import aubioinput
-
-win_s = 512                 # fft size
-hop_s = win_s / 2           # hop size
-beat = tempo("default", win_s, hop_s)
-
-beats = []
-
-def process(samples, pos):
-    isbeat = beat(samples)
-    if isbeat:
-        thisbeat = (float(isbeat[0]) + pos * hop_s) / 44100.
-        print thisbeat
-        beats.append (thisbeat)
-
-if len(sys.argv) < 2:
-    print "Usage: %s <filename>" % sys.argv[0]
-else:
-    filename = sys.argv[1]
-    a = aubioinput(filename, process = process, hopsize = hop_s,
-            caps = 'audio/x-raw-float, rate=44100, channels=1')
-    a.run()

diff --git a/interfaces/python/demo_beats_and_tempo.py b/interfaces/python/demo_beats_and_tempo.py
new file mode 100755 (executable)
index 0000000..7718145
--- /dev/null
+++ b/interfaces/python/demo_beats_and_tempo.py
@@ -0,0 +1,39 @@
+#! /usr/bin/python
+
+import sys
+from aubio import tempo, source
+
+win_s = 512                 # fft size
+hop_s = win_s / 2           # hop size
+samplerate = 44100
+
+if len(sys.argv) < 2:
+    print "Usage: %s <filename>" % sys.argv[0]
+    sys.exit(1)
+
+filename = sys.argv[1]
+beats = []
+
+s = source(filename, samplerate, hop_s)
+t = tempo("default", win_s, hop_s)
+
+block_read = 0
+while True:
+    samples, read = s()
+    isbeat = t(samples)
+    if isbeat:
+        thisbeat = (block_read * hop_s + isbeat[0]) / samplerate
+        print "%.4f" % thisbeat
+        beats.append (thisbeat)
+    block_read += 1
+    if read < hop_s: break
+
+periods = [60./(b - a) for a,b in zip(beats[:-1],beats[1:])]
+
+from numpy import mean, median
+print 'mean period:', mean(periods), 'bpm'
+print 'median period:', median(periods), 'bpm'
+
+from pylab import plot, show
+plot(beats[1:], periods)
+show()