Why do other tools turn my captions into boxes?

Most use FFmpeg's text filter, which needs the right font installed on the server and shows boxes when a glyph is missing. Here each caption is drawn to a transparent image with your own system fonts first, then composited onto the video.

Is there a limit on the number of cues?

150 per run. Beyond that, split the video with the Trim tool, burn each half, and join them again with Merge Videos.

Does it support ASS/SSA styling?

The text and timings are read, but effects such as karaoke timing and positioning animations are not preserved. Convert to SRT first.

Are my files uploaded to a server?

No. Everything runs locally in your browser via WebAssembly. Files never leave your computer and are discarded when you close the page.

Do I need to sign up or pay?

No. The site is completely free, requires no account, has no usage limits and adds no watermarks.

🔤

🔤Add Subtitles to Video Online - Burn SRT into the Picture

Burn SRT or WebVTT captions straight into the picture as hard subtitles, so they appear on every platform and in every player with no sidecar file. Text is rendered with the fonts on your own computer, so Chinese, Japanese and emoji never turn into empty boxes — and you can tune size, color, outline and the translucent background bar.

Free · No sign-up · Runs in your browserLast updated: 2026-10-26

Loading tool...

How to use Burn Subtitles

1Upload a video file
2Pick a .srt / .vtt file, or paste the subtitle text directly
3Adjust size, color, position and background, then click start

FAQ

Why do other tools turn my captions into boxes?: Most use FFmpeg's text filter, which needs the right font installed on the server and shows boxes when a glyph is missing. Here each caption is drawn to a transparent image with your own system fonts first, then composited onto the video.
Is there a limit on the number of cues?: 150 per run. Beyond that, split the video with the Trim tool, burn each half, and join them again with Merge Videos.
Does it support ASS/SSA styling?: The text and timings are read, but effects such as karaoke timing and positioning animations are not preserved. Convert to SRT first.
Are my files uploaded to a server?: No. Everything runs locally in your browser via WebAssembly. Files never leave your computer and are discarded when you close the page.
Do I need to sign up or pay?: No. The site is completely free, requires no account, has no usage limits and adds no watermarks.