python - Why my YouTube video downloader only downloads some videos and for other videos it shows keyerror like URL and cipher?

Question

I am trying to make a YouTube video downloader using Python pytube3 but it doesn't download all the videos. Some videos download very easily but some videos won't download and instead of download it shows error:

Exception in Tkinter callback
Traceback (most recent call last):
  File "C:\Users\tarun\PycharmProjects\YTDownloader\venv\lib\site-packages\pytube\extract.py", line 297, in apply_descrambler
    for format_item in formats
  File "C:\Users\tarun\PycharmProjects\YTDownloader\venv\lib\site-packages\pytube\extract.py", line 297, in <listcomp>
    for format_item in formats
KeyError: 'url'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "C:\Users\tarun\AppData\Local\Programs\Python\Python37-32\lib\tkinter\__init__.py", line 1705, in __call__
    return self.func(*args)
  File "C:/Users/tarun/PycharmProjects/YTDownloader/YTD.py", line 15, in video_download
    my_video = YouTube(input_user)
  File "C:\Users\tarun\PycharmProjects\YTDownloader\venv\lib\site-packages\pytube\__main__.py", line 92, in __init__
    self.descramble()
  File "C:\Users\tarun\PycharmProjects\YTDownloader\venv\lib\site-packages\pytube\__main__.py", line 132, in descramble
    apply_descrambler(self.player_config_args, fmt)
  File "C:\Users\tarun\PycharmProjects\YTDownloader\venv\lib\site-packages\pytube\extract.py", line 301, in apply_descrambler
    parse_qs(formats[i]["cipher"]) for i, data in enumerate(formats)
  File "C:\Users\tarun\PycharmProjects\YTDownloader\venv\lib\site-packages\pytube\extract.py", line 301, in <listcomp>
    parse_qs(formats[i]["cipher"]) for i, data in enumerate(formats)
KeyError: 'cipher'

Welcome to stackoverflow. Can you provide the code that is triggering the download? — Nico Müller

Shiven Saini Shiven Saini · Accepted Answer · 2020-05-31T12:04:27

This is an error in the file extract.py from pytube.

Go to the location where the package was installed. If you don't know where, run the command
```
pip show pytube3
```
And it'll give you something like this:

We can see Location: c:\users\tiago\anaconda3\lib\site-packages.

Go to that location, open the folder pytube and the file extract.py

In the file, line no. 306 or 301, you will find parse_qs(formats[i]["cipher"]). If yes, then change "cipher" to "signatureCipher" (make sure 'C' is capital).

So, you'll initially have

 cipher_url = [
                 parse_qs(formats[i]["cipher"]) for i, data in enumerate(formats)
             ]

but it should be

 cipher_url = [
                 parse_qs(formats[i]["signatureCipher"]) for i, data in enumerate(formats)
             ]

Run the following script to see it working

 # -*- coding: utf-8 -*-
 """
 Created on Mon Jun 15 12:21:49 2020

 @author: tiago
 """
 from pytube import YouTube

 video_url = "https://youtu.be/gp5tziO5lXg" # YouTube video URL
 youtube = YouTube(video_url)
 video = youtube.streams.first()
 video.download("C:/Users/tiago/Desktop/videos/") # Path where to store the video

You'll then see the video downloaded in that folder

python - Why my YouTube video downloader only downloads some videos and for other videos it shows keyerror like URL and cipher?

5 Answers