Ever wanted to automatically capture screenshots from a YouTube video every 10 seconds?

Or extract frames from a 3-hour lecture without manually pausing and screenshotting hundreds of times?

I built a Chrome extension to solve exactly that.

YouTube Screenshot Capture

Give Star To My Repo

GitHub: https://github.com/akshitsutharr/Youtube-Screen-capture

The Problem

Capturing screenshots manually from long YouTube videos is extremely inefficient:

• Pause → Screenshot → Play → Repeat


• No batch export


• No timestamp organization


• Hard to manage large videos


• Impossible to scale for 2–10 hour content

For students, researchers, analysts, and creators — this wastes hours.

So I built a solution.

What It Does

This Chrome Extension allows you to:

• Capture screenshots from any custom time range


• Set intervals from 1 second to 1 hour
  


• Automatically chunk videos longer than 1 hour


• Download all images as ZIP files


• Track progress in real time


• Choose screenshot quality (High / Medium / Low)

All processing happens locally inside your browser.

No servers.

No data collection.

No API keys.

Key Features

Custom Time Range

Supports both formats:

• MM:SS


• HH:MM:SS

Example:

• Start: 00:01:20
  


• End: 00:09:23
  

Flexible Intervals

Capture screenshots every:

• 1 second


• 5 seconds


• 10 seconds


• 30 seconds


• 1 minute


• Up to 1 hour

Smart Chunking (Large Video Support)

For videos longer than 1 hour:

The extension automatically splits processing into 1-hour chunks to prevent:

• Memory overflow


• Browser crashes


• Performance drops

This makes it capable of handling 10+ hour videos efficiently.

Bulk ZIP Download

Each capture session downloads:

• All screenshots in JPEG format


• Organized by timestamp


• 
  info.txt file with capture details

For long videos:

Multiple ZIP files are generated (one per hour chunk).

Real-Time Progress Tracking

You see:

• Percentage completed


• Screenshot count


• Processing updates

No guessing. No silent processing.

How It Works (Technical Deep Dive)

Tech Stack

• Manifest V3


• Canvas API


• JSZip


• Chrome Storage API


• Chrome Downloads API

Detecting the Video

The extension injects a content script that:

• Detects the <video> element


• Ensures it is playable


• Controls playback programmatically

Seeking to Specific Timestamps

For each interval:

video.currentTime = timestamp;

The extension waits for the seeked event before capturing.

Capturing Frames via Canvas API

const canvas = document.createElement("canvas");

const ctx = canvas.getContext("2d");

ctx.drawImage(video, 0, 0, width, height);

Convert to JPEG:

canvas.toBlob(...)

Intelligent Chunking Logic

To avoid memory crashes:

const CHUNK_DURATION = 3600; // 1 hour

Each chunk:

• Captures screenshots


• Packages them into ZIP


• Triggers download


• Frees memory


• Continues to next chunk

Performance Optimizations

During capture:

• Video auto-mutes


• Playback pauses for frame stability


• UI updates are throttled


• Object URLs are cleaned


• Memory is released per chunk

Example benchmark:

360 screenshots ≈ 2–3 minutes

Privacy & Permissions

Permissions required:

• activeTab


• storage


• downloads


• 
  host_permissions (only youtube.com)

Important:

• No data leaves your browser


• No tracking


• No analytics


• No external servers

Everything runs locally.

What I Learned Building This

This project helped me deeply understand:

• Chrome Extension architecture (Manifest V3)


• Content scripts vs background service workers


• Canvas-based video frame rendering


• Browser memory management


• Large file processing inside the browser


• Async UI state control

The hardest part?

Handling very large videos safely without crashing Chrome.

Chunking logic solved that.

Installation (Dev Mode)

1. Clone repository


2. Go to chrome://extensions
   


3. Enable Developer Mode


4. Click "Load Unpacked"


5. Select project folder

Done.

Future Improvements

Planned ideas:

• Chrome Web Store release


• Preset capture profiles


• Automatic keyframe detection


• Video metadata export


• PDF storyboard export

🤝 Contributions Welcome

If you're interested in:

• Chrome extension development


• Performance optimization


• UI improvements


• Feature additions

PRs are welcome.

🔗 GitHub:

https://github.com/akshitsutharr/Youtube-Screen-capture

🌟 Final Thoughts

This started as a small productivity tool.

But it turned into a deep dive into:

• Browser APIs


• Video processing


• Performance en

📸 Screenshots

Main Extension UI	Interval Selection

Downloading Start	Custom Button in Youtube for Single Capture