python/demos/demo_bpm_extract.py

   1 #! /usr/bin/env python
   2
   3 from aubio import source, tempo
   4 from numpy import median, diff
   5
   6 def get_file_bpm(path, params = None):
   7     """ Calculate the beats per minute (bpm) of a given file.
   8         path: path to the file
   9         param: dictionary of parameters
  10     """
  11     if params == None:
  12         params = {}
  13     try:
  14         win_s = params['win_s']
  15         samplerate = params['samplerate']
  16         hop_s = params['hop_s']
  17     except KeyError:
  18         """
  19         # super fast
  20         samplerate, win_s, hop_s = 4000, 128, 64
  21         # fast
  22         samplerate, win_s, hop_s = 8000, 512, 128
  23         """
  24         # default:
  25         samplerate, win_s, hop_s = 44100, 1024, 512
  26
  27     s = source(path, samplerate, hop_s)
  28     samplerate = s.samplerate
  29     o = tempo("specdiff", win_s, hop_s, samplerate)
  30     # List of beats, in samples
  31     beats = []
  32     # Total number of frames read
  33     total_frames = 0
  34
  35     while True:
  36         samples, read = s()
  37         is_beat = o(samples)
  38         if is_beat:
  39             this_beat = o.get_last_s()
  40             beats.append(this_beat)
  41             #if o.get_confidence() > .2 and len(beats) > 2.:
  42             #    break
  43         total_frames += read
  44         if read < hop_s:
  45             break
  46
  47     # Convert to periods and to bpm
  48     if len(beats) > 1:
  49         if len(beats) < 4:
  50             print("few beats found in {:s}".format(path))
  51         bpms = 60./diff(beats)
  52         b = median(bpms)
  53     else:
  54         b = 0
  55         print("not enough beats found in {:s}".format(path))
  56     return b
  57
  58 if __name__ == '__main__':
  59     import sys
  60     for f in sys.argv[1:]:
  61         bpm = get_file_bpm(f)
  62         print("{:6s} {:s}".format("{:2f}".format(bpm), f))