Step-by-Step Guide: How to Build a YouTube Downloader with Python

Building a YouTube downloader using pytube a Python library. pytube is a lightweight Python library used to download Youtube videos.

YouTube is one of the most popular video-sharing platforms on the internet. It hosts a vast amount of video content in various formats and resolutions. While YouTube allows users to watch videos online, it does not provide an option to download videos.

In this article, we will learn how to build a YouTube downloader using Python, allowing us to download videos from YouTube in various formats and resolutions.

Prerequisites: Thinks You Should Have Before You Start!

• Before we begin, you should know the basic norms of Python programming language and its concepts.
• You should also have Python installed on your computer.
• Additionally, you need to have the pytube library installed. (You can use pip command to install)

Let’s start with pytube installation process.

You can install the pytube library by running the following command in your terminal or command prompt. pip is a package manager for Python used to install libraries or modules ina programmable environment.

pip install pytube

Getting Started with YouTube Video Downloader

To download a video from YouTube, we need first to retrieve the URL of the video. You can obtain the URL by visiting the YouTube video page and copying the URL from the address bar of your browser. Alternatively, you can search for the video using the YouTube search bar and then copy the URL from the search results.

After we have obtained the URL of the video, we can use the pytube library to download the video. The pytube library provides a YouTube class, which represents a YouTube video. We can create an instance of the YouTube class by passing the video URL to the constructor.

from pytube import YouTube

url = 'https://youtu.be/Gc5L3qO5hKs'
video = YouTube(url)

Once we have created an instance of the YouTube class, we can access various properties of the video, such as its title, description & thumbnail. We can print the title of the video using the title property of the YouTube object.

print(video.title)

Addition Video Attributes

Further, it also provides some additional facilities including number of views, description of video, length of video, and ratings to the video.

#number of views of video
print("Number of views: ",video.views)

#length of the video
print("\n\nLength of video: ",video.length,"seconds")

#rating of video
print("\n\nRatings: ",video.rating)

Code Output

Selecting a Video Stream: Time to Choose a Video Resolution & Format

YouTube videos can be streamed in various formats and resolutions. To download a video, we need to select a specific video stream that matches our requirements. The pytube library provides a streams property of the YouTube object, which returns a list of all available video streams for the video.

streams = video.streams.all()

We can filter the list of streams based on our requirements. For example, we may want to select only the video streams that are in the MP4 format and have a resolution of 720p or higher. We can use the filter method of the list to filter the streams based on the video format and resolution.

streams = video.streams.filter(file_extension='mp4', resolution='720p')

The filter method returns a list of streams that match the specified criteria. We can then select a specific stream from the list based on our preferences. For example, we can select the first stream from the list using the first method.

stream = streams.first()

Downloading the Video: Finally the wait is over!

Once we have selected a video stream, we can download the video using the download() method of the stream object. The download() method takes an optional parameter output_path, which specifies the directory where the downloaded video should be saved. If the output_path parameter is not specified, the video will be saved in the current working directory.

stream.download(output_path='/path/to/directory')

The download() method downloads the video in the specified format and resolution. The download process may take some time, depending on the size of the video and your internet speed.

Putting it All Together: Complete Project

Here is the complete code for a basic YouTube downloader using Python:

from pytube import YouTube

# enter the url of the YouTube video you want to download
url = 'https://www.youtube.com/watch?v=dQw4w9WgXcQ'

# create a YouTube object
video = YouTube(url)

# print the title of the video
print(video.title)

# select the highest resolution progressive video and audio stream
stream = video.streams.filter(progressive=True, file_extension='mp4').order_by('resolution').desc().first()

# download the video
stream.download()

• Line#1: This line imports the YouTube class from the pytube module, which is a library for downloading YouTube videos using Python.
• Line#4: This line assigns a string value to the variable 'url', which contains the URL of the YouTube video we want to download.
• Line#7: This line creates an instance of the YouTube class and passes the 'url' variable as an argument to the constructor, which creates a new object that represents the YouTube video.
• Line#10: This line calls the 'title' method on the 'video' object and prints the title of the YouTube video to the console.
• Line#13: This line selects the highest resolution progressive video and audio stream from the ‘video’ object. The 'streams' property of the YouTube object contains a list of all available video and audio streams for the video. The 'filter' method is used to select only the streams that have a progressive file format and an mp4 file extension. The 'order_by' method sorts the list of streams by resolution in descending order, so the highest resolution stream is first. Finally, the 'first' method is used to select the first (i.e., highest resolution) stream from the sorted list.
• Line#16: This line downloads the video using the 'download' method of the 'stream' object, which saves the video to the current working directory.

The Final Verdict

In this article, we’ve shown you how to build a YouTube downloader with Python, using the pytube library. With just a few lines of code, you can download videos from YouTube to watch offline or for other purposes.

However, it’s important to note that downloading videos from YouTube may violate the platform’s terms of service, and you should only do so for personal or educational purposes.