From e6f7a4af72f020ac14ad45efd6f52e6aa961a34c Mon Sep 17 00:00:00 2001
From: Paul Brossier <piem@piem.org>
Date: Fri, 8 Mar 2013 10:12:17 -0500
Subject: [PATCH] demos/demo_onset.py: add simple onset example, update
 demo_onset_plot.py

---
 python/demos/demo_onset.py                    | 37 +++++++++++++++++++
 ...{demo_onset_file.py => demo_onset_plot.py} | 33 +++++++++++------
 2 files changed, 58 insertions(+), 12 deletions(-)
 create mode 100755 python/demos/demo_onset.py
 rename python/demos/{demo_onset_file.py => demo_onset_plot.py} (76%)

diff --git a/python/demos/demo_onset.py b/python/demos/demo_onset.py
new file mode 100755
index 00000000..20e7bf05
--- /dev/null
+++ b/python/demos/demo_onset.py
@@ -0,0 +1,37 @@
+#! /usr/bin/env python
+
+import sys
+from aubio import onset, source
+from numpy import array, hstack, zeros
+
+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 = onset("default", win_s, hop_s)
+
+# onset detection delay, in blocks
+delay = 4. * hop_s
+
+onsets = []
+total_frames = 0
+while True:
+    samples, read = s()
+    is_onset = o(samples)
+    if is_onset:
+        this_onset = int(total_frames - delay + is_onset[0] * hop_s)
+        print "%f" % (this_onset / float(samplerate))
+        onsets.append(this_onset)
+    total_frames += read
+    if read < hop_s: break
+#print len(onsets)
diff --git a/python/demos/demo_onset_file.py b/python/demos/demo_onset_plot.py
similarity index 76%
rename from python/demos/demo_onset_file.py
rename to python/demos/demo_onset_plot.py
index fe13cd7d..cfdf16b9 100755
--- a/python/demos/demo_onset_file.py
+++ b/python/demos/demo_onset_plot.py
@@ -6,36 +6,45 @@ from numpy import array, hstack, zeros
 
 win_s = 512                 # fft size
 hop_s = win_s / 2           # hop size
-samplerate = 44100
-downsample = 2              # used to plot n samples / hop_s
 
 if len(sys.argv) < 2:
-    print "Usage: %s <filename>" % sys.argv[0]
+    print "Usage: %s <filename> [samplerate]" % sys.argv[0]
     sys.exit(1)
 
 filename = sys.argv[1]
-onsets = []
+
+samplerate = 0
+if len( sys.argv ) > 2: samplerate = int(sys.argv[2])
 
 s = source(filename, samplerate, hop_s)
+samplerate = s.samplerate
 o = onset("default", win_s, hop_s)
 
+# onset detection delay, in blocks
+delay = 4. * hop_s
+
+onsets = []
+
+# storage for plotted data
 desc = []
 tdesc = []
-
-block_read = 0
 allsamples_max = zeros(0,)
+downsample = 2  # to plot n samples / hop_s
+
+total_frames = 0
 while True:
     samples, read = s()
+    is_onset = o(samples)
+    if is_onset:
+        this_onset = int(total_frames - delay + is_onset[0] * hop_s)
+        print "%f" % (this_onset / float(samplerate))
+        onsets.append(this_onset / float(samplerate))
+    # 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])
-    isbeat = o(samples)
     desc.append(o.get_descriptor())
     tdesc.append(o.get_thresholded_descriptor())
-    if isbeat:
-        thisbeat = (block_read - 4. + isbeat[0]) * hop_s / samplerate
-        print "%.4f" % thisbeat
-        onsets.append (thisbeat)
-    block_read += 1
+    total_frames += read
     if read < hop_s: break
 
 if 1:
-- 
2.26.2