Free Online Subtitle Burner
Hardcode SRT or VTT subtitles into any video so they show on every player and platform. Runs entirely in your browser via WebAssembly — no upload, no watermark, no signup.
Features
Permanent Captions Everywhere
Hardcode SRT or VTT subtitles directly into the video frames so they play back on every device, app, and social platform — no separate file, no player support needed.
SRT & VTT Support
Drop the two most common subtitle formats — SubRip (.srt) or WebVTT (.vtt) — and SubFuse renders them straight into the video.
Plays on Every Platform
Burned-in captions show on Instagram, TikTok, YouTube Shorts, WeChat, and any silent autoplay feed where soft subtitles are ignored.
Pick the Right Font Size
Choose Small, Medium, or Large to match your video's resolution and viewing context — perfect for both phones and desktop.
Quality Preserved
High-quality H.264 re-encoding keeps the picture sharp while audio is copied through untouched. Subtitles are rendered as crisp, pixel-perfect overlays.
H.264 Veryfast Preset
Re-encodes with CRF 23 so output is visually indistinguishable from the source — even fine details and gradients survive.
Audio Passed Through
The original audio track is copied without re-encoding — identical sound, zero loss.
Faststart MP4
Output MP4 has the moov atom at the front, so it starts playing instantly when shared online.
100% Private & Free
Your video and subtitle file never leave your device — everything runs in the browser tab using WebAssembly.
Zero Server Upload
Files are read, processed, and written back entirely on your own machine. No cloud, no database, no logs.
No Watermark
The exported video is clean — no logo, no stamp, no branding overlay.
Works Everywhere
Any modern browser — desktop or mobile. Chrome, Firefox, Safari, Edge.
FAQ'S
Frequently Asked Questions
Ask us anything!
Burn Subtitles Into Your Video Now
Free, private, and instant. No signup, no upload, no watermark — drop your video and SRT, pick a font size, and download an MP4 with permanent captions baked in.