Video Subtitle Tool | Add & Edit Video Captions Online | Factictionary

Video Subtitle Tool

Add, edit, and style video captions and subtitles with real-time preview. Support for SRT files, custom styling, timing adjustment, and video processing. Perfect for content creators, educators, and accessibility.

⌨️ Keyboard Shortcuts

Space Play/Pause Ctrl + ← Rewind 10s Ctrl + → Forward 10s Ctrl + N Add subtitle Ctrl + S Sync to video
🔒 100% Privacy Protected
SRT Support Real-time Preview Custom Styling Timing Control Drag & Drop Video Download

How to Use

1

Upload Files

Drag & drop your video file and SRT subtitle file, or click to browse and select files.

2

Edit Subtitles

Click on any subtitle in the timeline to edit text, timing, and position. Use the video controls to sync with specific moments.

3

Style Your Subtitles

Customize font, colors, position, background, and effects to match your video's style.

4

Process & Download

Click "Process Video" to generate your video with embedded subtitles. Download the final result when ready.

Upload Files

Subtitle Editor

Subtitle Timeline

📝 Upload SRT file or add subtitles manually

Edit Subtitle

Subtitle Styling

🎨 Text Style

24px

📍 Position & Layout

20%

🎭 Background & Effects

70%
0px

⚙️ Advanced

Processing & Export

🔒

100% Privacy Protected

All processing is done locally in your browser. Your video and subtitle files never leave your device.

How to Use the Video Subtitle

Using our Video Subtitle is designed to be completely frictionless. Simply upload your files using the drag-and-drop interface or click to browse your device. Once selected, configure the settings to your exact specifications. When ready, click the process button. The operation runs entirely within your browser, ensuring maximum privacy and speed without relying on external servers. Finally, download your processed file directly to your system.

Technical Explanation

The Video Subtitle leverages advanced client-side processing technologies to manipulate data directly on your device. Instead of uploading your sensitive files to a remote server—which carries significant privacy risks and consumes massive bandwidth—this tool utilizes HTML5 File APIs, WebAssembly, and native JavaScript array buffers.

When you initiate the process, the application reads the file into memory using a FileReader. It then applies complex algorithms—such as compression heuristics, codec transformations, or binary manipulation—depending on the specific task. The output is dynamically generated as a Blob object, which the browser then prompts you to download. This architecture guarantees that your data never leaves your machine.