Get .wav file length or duration

Question

I\'m looking for a way to find out the duration of a audio file (.wav) in python. So far i had a look at python wave library, mutagen, pymedi

Answer 1

import os
path="c:\\windows\\system32\\loopymusic.wav"
f=open(path,"r")

#read the ByteRate field from file (see the Microsoft RIFF WAVE file format)
#https://ccrma.stanford.edu/courses/422/projects/WaveFormat/
#ByteRate is located at the first 28th byte
f.seek(28)
a=f.read(4)

#convert string a into integer/longint value
#a is little endian, so proper conversion is required
byteRate=0
for i in range(4):
    byteRate=byteRate + ord(a[i])*pow(256,i)

#get the file size in bytes
fileSize=os.path.getsize(path)  

#the duration of the data, in milliseconds, is given by
ms=((fileSize-44)*1000)/byteRate

print "File duration in miliseconds : " % ms
print "File duration in H,M,S,mS : " % ms/(3600*1000) % "," % ms/(60*1000) % "," % ms/1000 % "," ms%1000
print "Actual sound data (in bytes) : " % fileSize-44  
f.close()

Answer 2

Let,T be the duration between 2 consecutive samples. So, we can write t = nT or t = n/Fs.

from scipy.io import wavfile
Fs, data = wavfile.read('filename.wav')
n = data.size
t = n / Fs

Answer 3

I was trying to get the length of different format of an audio file other than '.wav' and I tried a few of the above solution but didn't work for me

This is what worked for me :

from pydub.utils import mediainfo
mediainfo('audiofile')['duration']

Answer 4

To find length of music file, audioread module can be used,

install audioread: pip install audioread

then use this code:

import audioread
with audioread.audio_open(filepath) as f:
    totalsec = f.duration
    min,sec = divmod(totalsec,60) # divides total time in minute  and second 
                                    #and store it in min and sec variable respectively

Answer 5

the librosa library can do this: librosa

import librosa
librosa.get_duration(filename='my.wav')

Answer 6

The duration is equal to the number of frames divided by the framerate (frames per second):

import wave
import contextlib
fname = '/tmp/test.wav'
with contextlib.closing(wave.open(fname,'r')) as f:
    frames = f.getnframes()
    rate = f.getframerate()
    duration = frames / float(rate)
    print(duration)

---

Regarding @edwards' comment, here is some code to produce a 2-channel wave file:

import math
import wave
import struct
FILENAME = "/tmp/test.wav"
freq = 440.0
data_size = 40000
frate = 1000.0
amp = 64000.0
nchannels = 2
sampwidth = 2
framerate = int(frate)
nframes = data_size
comptype = "NONE"
compname = "not compressed"
data = [(math.sin(2 * math.pi * freq * (x / frate)),
        math.cos(2 * math.pi * freq * (x / frate))) for x in range(data_size)]
try:
    wav_file = wave.open(FILENAME, 'w')
    wav_file.setparams(
        (nchannels, sampwidth, framerate, nframes, comptype, compname))
    for values in data:
        for v in values:
            wav_file.writeframes(struct.pack('h', int(v * amp / 2)))
finally:
    wav_file.close()

If you play the resultant file in an audio player, you'll find that is 40 seconds in duration. If you run the code above it also computes the duration to be 40 seconds. So I believe the number of frames is not influenced by the number of channels and the formula above is correct.