A Complete Guide to Python Convert MP4 to MP3 with MoviePy – Python Tutorial

By | October 18, 2019

Python moviepy library can convert mp4 to mp3 easily, in this tutorial, we will write an example to discuss how to convert, you can follow our steps to learn how to do.

Install moviepy

You can use pip command to install moviepy library

pip install moviepy

If you are using anaconda, you also can use conda command to install.

conda install -c conda-forge moviepy

Import moviepy library

from moviepy.editor import *

Set mp4 file and mp3 file 

You can set the file name of mp4 and mp3.

mp4_file = r'E:\VID_20180308_141907.mp4'
mp3_file = r'E:\VID_20180308_141907.mp3'

Convert mp4 to mp3 using python moviepy

In this example, we use mp4 file to create a VideoFileClip object, then get the audo object of this mp4 file, finally save the audo of this mp4 into a mp3 file.

The example code is:

videoclip = VideoFileClip(mp4_file)

audioclip = videoclip.audio
audioclip.write_audiofile(mp3_file)

audioclip.close()
videoclip.close()

Run this python script, you will find result like:

moviepy convert mp4 to mp3

Then convert mp4 to mp3 successfully.

Notice: When you are converting, you may find error like:

AttributeError: cffi library ‘_openssl’ has no function, constant or global variable named ‘Cryptography_HAS_ECDH’

To fix this error, you can check this tutorial.

Fix AttributeError: cffi library ‘_openssl’ has no function, constant or global variable named ‘Cryptography_HAS_ECDH’

2 thoughts on “A Complete Guide to Python Convert MP4 to MP3 with MoviePy – Python Tutorial

  1. tibo

    Hello

    How would it to convert contents downloaded with requests.get, without saving to disk?

    The method
    audioclip.write_audiofile(mp3_file)
    Requires a filename.

    If I put instead:
    audioclip.write_audiofile(r.content)

    I’ve got an error

    Reply
    1. admin Post author

      audioclip.write_audiofile(mp3_file), it means convert mp4 file to mp3 file and save it.
      However, if you have downloaded a mp4 from Internet and use a python variable mp4_data to save its content.
      You can not use VideoFileClip(mp4_data), because VideoFileClip need a filename.
      It will call
      self.reader = FFMPEG_VideoReader(filename, pix_fmt=pix_fmt,
      target_resolution=target_resolution,
      resize_algo=resize_algorithm,
      fps_source=fps_source)

      by filename.
      FFMPEG_VideoReader will this filename to call
      def ffmpeg_parse_infos(
      filename, print_infos=False, check_duration=True, fps_source="tbr"
      )

      This code will call ffmpeg command to convert mp4 file.
      https://github.com/Zulko/moviepy/blob/c8d02deea741be7f4196a31ea7ee0863769ca5b1/moviepy/video/io/ffmpeg_reader.py#L256
      You can use a temporary file to save mp4 data, and delete it after having converted successfully. This is a good way, beacuse you may fail to convert, you can convert it again by avoiding to download mp4 file again.

      Reply

Leave a Reply

Your email address will not be published. Required fields are marked *