How do we download a blob url video

Learn how do we download a blob url video with practical examples, diagrams, and best practices. Covers video, browser, blob development techniques with visual explanations.
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Downloading Blob URL Videos: A Comprehensive Guide

Illustration of a video player with a download icon and a blob shape, representing downloading blob URL videos.

Learn how to effectively download videos served via Blob URLs in your browser, covering common scenarios and technical approaches.

Blob URLs (Binary Large Object URLs) are temporary, client-side URLs that reference data stored in the browser's memory. They are often used for media playback, especially when content is generated dynamically or loaded from a source that doesn't provide a direct downloadable link. While convenient for streaming, downloading videos from blob URLs can be tricky because they don't point to a persistent file on a server. This article will guide you through various methods to capture and download these videos.

Understanding Blob URLs and Their Challenges

A Blob URL typically looks like blob:http://example.com/some-uuid. It's a local reference, not a network address. When a video player uses a blob URL, it's essentially playing data that the browser has already fetched and stored temporarily. The main challenge in downloading such videos is that there's no direct 'download' button or server-side file to link to. The data exists only within the browser's current session.

This often requires intercepting the underlying network requests that populate the blob, or extracting the data directly from the browser's memory or developer tools. The approach you take depends on how the blob was generated and the level of access you have to the page's source.

flowchart TD
    A[User Navigates to Page]
    B[Page Loads Video Player]
    C{Video Source: Direct URL or Blob?}
    C -->|Direct URL| D[Standard Download Possible]
    C -->|Blob URL| E[Blob Data Generated/Fetched]
    E --> F[Video Plays from Blob]
    F --> G{User Wants to Download}
    G -->|Attempt Direct Download| H[Fails: No Server File]
    G -->|Use Dev Tools/Scripting| I[Intercept Network Request]
    G -->|Use Dev Tools/Scripting| J[Extract Blob Data]
    I --> K[Reconstruct Video File]
    J --> K
    K --> L[Save Video to Disk]
    style D fill:#bbf,stroke:#333,stroke-width:2px
    style L fill:#bbf,stroke:#333,stroke-width:2px

Process of playing and attempting to download a video from a Blob URL.

Method 1: Using Browser Developer Tools

The most common and often simplest way to download a blob URL video is by leveraging your browser's developer tools. This method usually involves inspecting the network requests or directly accessing the blob data.

Sub-method A: Network Tab Inspection

Many blob URLs are generated from data that was originally fetched via a standard HTTP request. If you can find this original request, you might be able to download the raw video file directly.

Sub-method B: Direct Blob Data Extraction

If the video data is already in the browser's memory as a Blob object, you can sometimes access it directly through the Console tab and create a downloadable link.

1. Open Developer Tools

In your browser (Chrome, Firefox, Edge), right-click on the video element or anywhere on the page and select 'Inspect' or 'Inspect Element'. Alternatively, use F12 or Ctrl+Shift+I (Windows/Linux) / Cmd+Option+I (macOS).

2. Navigate to Network Tab

Go to the 'Network' tab within the Developer Tools. It's crucial to clear any existing network logs and then refresh the page or restart the video playback to capture all relevant requests.

3. Identify Video Request

Look for requests with a 'Media' or 'XHR' type. Filter by 'Media' or 'Doc' or 'XHR' and look for large files or files with video-related extensions (e.g., .mp4, .webm, .ts). Sometimes, the actual video data is fetched in chunks (e.g., .ts files for HLS streams). If you find a direct video file, right-click it and choose 'Open in new tab' or 'Save as...'. If it's a series of chunks, you might need a specialized tool like youtube-dl or ffmpeg to stitch them together.

4. Extract Blob URL (if direct download fails)

If you can't find a direct video file in the Network tab, go to the 'Elements' tab. Find the <video> tag. It will likely have a src attribute pointing to the blob URL (e.g., src="blob:http://example.com/some-uuid"). Copy this URL. Then, switch to the 'Console' tab.

In the Console, you can try to access the Blob object directly. Paste the following JavaScript code, replacing yourBlobUrl with the actual blob URL you copied:

fetch('yourBlobUrl')
  .then(response => response.blob())
  .then(blob => {
    const url = URL.createObjectURL(blob);
    const a = document.createElement('a');
    a.href = url;
    a.download = 'downloaded_video.mp4'; // You might need to adjust the filename and extension
    document.body.appendChild(a);
    a.click();
    document.body.removeChild(a);
    URL.revokeObjectURL(url);
  })
  .catch(e => console.error('Error downloading blob:', e));

Press Enter. Your browser should prompt you to download the video. Note that the filename and extension might need manual adjustment based on the actual video type.

Method 2: Using External Tools (youtube-dl/yt-dlp)

For more complex scenarios, especially with streaming services or sites that employ advanced anti-download measures, command-line tools like youtube-dl or its actively maintained fork yt-dlp are invaluable. These tools are designed to parse web pages, identify video sources (including various streaming formats like HLS and DASH), and download them, often bypassing blob URL complexities by targeting the underlying stream.

While youtube-dl and yt-dlp are primarily known for YouTube, they support thousands of other websites. They work by analyzing the page's JavaScript and network requests to find the actual video manifest or segments, then reassembling them into a single file.

# Install yt-dlp (recommended over youtube-dl)
pip install yt-dlp

# Basic usage: Replace with the actual page URL containing the video
yt-dlp "https://example.com/page-with-blob-video"

# If yt-dlp needs cookies for authentication (e.g., logged-in content)
yt-dlp --cookies-from-browser chrome "https://example.com/page-with-blob-video"

# Specify output format or quality
yt-dlp -f bestvideo+bestaudio --merge-output-format mp4 "https://example.com/page-with-blob-video"

Example commands for downloading videos using yt-dlp.

Method 3: Browser Extensions

A less technical approach involves using browser extensions designed for media downloading. While many extensions struggle with true blob URLs, some are sophisticated enough to detect and download media streams that feed into blob objects. Search your browser's extension store for 'video downloader' or 'stream downloader' extensions. Always check reviews and permissions before installing any extension.

Downloading videos from blob URLs can range from a simple console command to a more involved process of network analysis. By understanding how blob URLs work and utilizing browser developer tools or external utilities like yt-dlp, you can successfully capture and save the video content you need. Remember to respect content copyrights and terms of service when downloading media.