ASCII Waveform Generator

asciiwaveform.py

import argparse
import subprocess
import sys
import tempfile

def generate_view(infile, wave_width, wave_height):
  _, datfilename = tempfile.mkstemp(suffix='.dat')
  datfile = open(datfilename, 'r')
  p = subprocess.Popen(['sox', infile, datfilename], 
      stdout=subprocess.PIPE, stderr=subprocess.PIPE)

  p.communicate()

  amplitudes = [abs(float(v.split()[1])) for v in datfile.readlines()[2:]]

  num_ivals = len(amplitudes) / wave_width
  ival_len = len(amplitudes) % wave_width

  avg_amplitudes = []
  for i in range(wave_width):
    start_ival = int(i * num_ivals + min(i, ival_len))
    end_ival = int((i + 1) * num_ivals + min(i + 1, ival_len))
    ival = amplitudes[start_ival:end_ival]
    avg_amplitudes.append(sum(ival)/len(ival))

  upper_rows = []
  wave_marker = {True: '|'}
  for y in reversed(range(wave_height)):
    row = []
    for amp in avg_amplitudes:
      row.append(wave_marker.get(amp > y * (.5/wave_height), ' '))
    upper_rows.append(row)

  lower_rows = [r for r in reversed(upper_rows[:-1])]

  ascii_waveform = ''
  for row in upper_rows + lower_rows:
    row_output = ''.join(row)
    ascii_waveform += ''.join(row) + '\n'

  return ascii_waveform

def main():
  parser = argparse.ArgumentParser()
  parser.add_argument('-i', '--infile', help='a sound file')
  parser.add_argument('-y', '--width', type=int, default=80,
    help='the width of the desired waveform output in characters')
  parser.add_argument('-x', '--height', type=int, default=20,
    help='the height of the desired waveform in characters')

  args = parser.parse_args()

  print(generate_view(args.infile, args.width, args.height))

if __name__ == '__main__':
  main()