Building a YouTube Video Downloader in Python

Introduction

Downloading videos from YouTube is a popular automation task for offline viewing, content archiving, and educational use. Python offers an excellent library called pytube that makes this process simple and effective.

In this article, you’ll learn how to create a YouTube video downloader that:

• Accepts a YouTube video URL

• Lists available video streams (resolutions and formats)

• Downloads the selected stream to your local machine

Let’s walk through it step by step.

Step 1: Install Required Library

We will use the pytube library. You can install it using pip:

pip install pytube

Note: If you're behind a firewall or experience issues, upgrade using:

pip install --upgrade pytube

Step 2: Import Necessary Modules

Start your Python script by importing the required module.

from pytube import YouTube

We only need YouTube from pytube, which allows us to work with video objects and streams.

Step 3: Get the YouTube Video URL

Prompt the user to enter a video URL.

video_url = input("Enter the YouTube video URL: ")

This URL will be passed to the YouTube class to initialize the video object.

Step 4: Initialize the YouTube Object

try:
    yt = YouTube(video_url)
    print(f"\nTitle: {yt.title}")
    print(f"Author: {yt.author}")
    print(f"Length: {yt.length} seconds")
except Exception as e:
    print("Error loading video:", e)
    exit()

This block:

• Initializes the video

• Displays some basic information

• Handles errors gracefully (invalid links, network issues, etc.)

Step 5: List Available Streams

Now, we’ll list all available video streams with progressive download (video + audio combined).

streams = yt.streams.filter(progressive=True).order_by('resolution').desc()

print("\nAvailable Streams:")
for i, stream in enumerate(streams):
    print(f"{i + 1}. {stream.resolution} - {stream.mime_type}")

• .filter(progressive=True) ensures the streams include both video and audio.

• .order_by('resolution') sorts them by quality.

Step 6: Choose and Download a Stream

Let the user choose a stream number and download the corresponding file.

try:
    choice = int(input("\nEnter the number of the stream to download: "))
    selected_stream = streams[choice - 1]

    print("Downloading...")
    selected_stream.download()
    print("Download complete!")

except (IndexError, ValueError):
    print("Invalid choice.")

• The .download() method saves the file in the current working directory.

• You can also pass a folder path to download() if you want to change the location.

Full Script: YouTube Video Downloader in One Go

from pytube import YouTube

# Step 1: Get video URL from user
video_url = input("Enter the YouTube video URL: ")

# Step 2: Initialize the YouTube object
try:
    yt = YouTube(video_url)
    print(f"\nTitle: {yt.title}")
    print(f"Author: {yt.author}")
    print(f"Length: {yt.length} seconds")
except Exception as e:
    print("Error loading video:", e)
    exit()

# Step 3: List available progressive streams
streams = yt.streams.filter(progressive=True).order_by('resolution').desc()

print("\nAvailable Streams:")
for i, stream in enumerate(streams):
    print(f"{i + 1}. {stream.resolution} - {stream.mime_type}")

# Step 4: Get user choice and download
try:
    choice = int(input("\nEnter the number of the stream to download: "))
    selected_stream = streams[choice - 1]

    print("Downloading...")
    selected_stream.download()
    print("Download complete!")

except (IndexError, ValueError):
    print("Invalid choice.")

Optional Enhancements

1. Download only audio
   Add an option to filter audio streams:

    yt.streams.filter(only_audio=True)
   

2. Choose download folder

    selected_stream.download(output_path="C:/Users/You/Downloads")
   

3. Show file size before downloading

    print(f"File size: {round(selected_stream.filesize / 1024 / 1024, 2)} MB")
   

Conclusion

With just a few lines of Python, you’ve built a powerful YouTube downloader that lets users choose video quality and download content locally. It’s a great example of how to interact with web services and media files using Python.