Download video in mp3 format using pytube

Question

I have been using pytube to download youtube videos in python. So far I have been able to download in mp4 format.

yt = pytube.YouTube("https://www.youtube.com/watch?v=WH7xsW5Os10")

vids= yt.streams.all()
for i in range(len(vids)):
    print(i,'. ',vids[i])

vnum = int(input("Enter vid num: "))
vids[vnum].download(r"C:\YTDownloads")
print('done')

I managed to download the 'audio' version, but it was in .mp4 format. I did try to rename the extension to .mp3, and the audio played, but the application (Windows Media Player) stopped responding and it began to lag.

How can I download the video as an audio file, in .mp3 format directly? Please provide some code as I am new to working with this module.

Answer 1

How can I download the video as an audio file, in .mp3 format directly?

I'm afraid you can't. The only files available for direct download are the ones which are listed under yt.streams.all().

However, it is straightforward to convert the downloaded audio file from .mp4 to .mp3 format. For example, if you have ffmpeg installed, running this command from the terminal will do the trick (assuming you're in the download directory):

$ ffmpeg -i downloaded_filename.mp4 new_filename.mp3

Alternatively, you can use Python's subprocess module to execute the ffmpeg command programmatically:

import os
import subprocess

import pytube

yt = pytube.YouTube("https://www.youtube.com/watch?v=WH7xsW5Os10")

vids= yt.streams.all()
for i in range(len(vids)):
    print(i,'. ',vids[i])

vnum = int(input("Enter vid num: "))

parent_dir = r"C:\YTDownloads"
vids[vnum].download(parent_dir)

new_filename = input("Enter filename (including extension): "))  # e.g. new_filename.mp3

default_filename = vids[vnum].default_filename  # get default name using pytube API
subprocess.run([
    'ffmpeg',
    '-i', os.path.join(parent_dir, default_filename),
    os.path.join(parent_dir, new_filename)
])

print('done')

EDIT: Removed mention of subprocess.call. Use subprocess.run (unless you're using Python 3.4 or below)