Extracted mp3 file is longer than the original mp4 file.

[Pimool]

Hi, I'm trying to extract audio from mp4 file and save it as mp3 file with using moviepy.

However, the playtime of mp3 file(output) and mp4 file(input) are different.

I guess it's a problem of fps, but I cannot handle it.

from moviepy.editor import *

clip = VideoFileClip('video.mp4')
print(clip.fps)
print(clip.duration)
audio_clip = clip.audio
print(audio_clip.fps)
print(audio_clip.duration)
audio_clip.write_audiofile('audio.mp3', logger = None)
audio_clip.close()
clip.close()

Output :

29.97002997002997
2322.28
44100
2322.28

The converted audio(mp3) file's playtime is 39:41 while video(mp4) file's playtime is 38:42

I'm trying to make a transcript of video file by converting into mp3 file, so the time difference is very crucial to me.

Can anyone help?

[Pimool]

With a lot of search, I found the solution.

It's a problem with ffmpeg.

Pass '-write_xing 0' as a ffmpeg parameter.

Example :

from moviepy.editor import *

clip = VideoFileClip('video.mp4')
audio_clip = clip.audio
audio_clip.write_audiofile('audio.mp3', logger = None, ffmpeg_params = ["-write_xing", "0"])

You can also use it when using pydub.

from pydub import AudioSegment

audio = AudioSegment.from_mp3(audio_file_path)
audio.export(path, format = 'mp3', parameters = ["-write_xing", "0"])

References https://superuser.com/questions/607703/wrong-audio-duration-with-ffmpeg https://trac.ffmpeg.org/ticket/2697