https://jip.debeer.it/friends-season-1-an-average-episode

average_wav.py

import os, numpy as np
from scipy.io import wavfile

def show_info(aname, a):
    print "Array", aname
    print "shape:", a.shape
    print "dtype:", a.dtype
    print "min, max:", a.min(), a.max()

audio_folder_name = 'right_audio_track'

# Access all WAV files in directory
allfiles=os.listdir(os.path.join(os.getcwd(), audio_folder_name))
wav_filenames = [filename for filename in allfiles if  filename[-4:] in [".wav",".WAV"]]

rate = 0
max_size = 0
dtype = np.int32 # set as default

wav_list = []

for filename in wav_filenames:
    rate, data = wavfile.read(os.path.join(os.getcwd(), audio_folder_name, filename))
    # store the data for later
    wav_list.append(data)
    show_info(filename, data)
    if (data.shape[0] > max_size):
        max_size = data.shape[0]
        dtype = data.dtype # override default

# int64 will overflow and as a result clip the audo if the sum of the sample
# values is smaller than -9223372036854775808 or larger than 9223372036854775807
newdata = np.zeros((max_size,), dtype=np.int64)

for wav in wav_list:
    # resize the data to equal lengths and add them together
    wav.resize((max_size,), refcheck=False)
    newdata = newdata + wav

# average the audio
newdata = newdata / len(wav_list)

# Write the data
wavfile.write(os.path.join(os.getcwd(), audio_folder_name + '_average.wav'), rate, newdata.astype(dtype))