What is the difference between burn-in and soft subtitles?

Burn-in renders the captions directly onto every video frame so they appear in any player — but they cannot be turned off. Soft subtitles are stored as a separate text track inside the MP4 and can be toggled on or off by the viewer in compatible players.

Which subtitle file formats are supported?

SRT is the most reliable and is recommended. VTT (WebVTT) is also accepted; ffmpeg converts it internally as needed. Make sure the file is plain text and saved with UTF-8 encoding.

Will burn-in re-encode the video?

Yes. Burning subtitles into the picture requires re-rendering every frame, so the video stream is re-encoded with the H.264 ultrafast preset. Soft mode stream-copies the video and is much faster.

Why are my subtitles not appearing in soft mode?

Soft subtitles need a player that supports MP4 mov_text — most modern players including VLC, mpv and YouTube uploads handle them. iOS Safari and QuickTime can be inconsistent; use burn-in if you target those.

Can I style the burnt-in subtitles?

This tool uses ffmpeg defaults — white text with a subtle outline at a readable size. For advanced styling (font, color, position), edit the SRT into an ASS file with explicit formatting before encoding.

Is anything uploaded to a server?

No. Both the video and the subtitle file are processed locally inside your browser via WebAssembly. Nothing leaves your device.

Add Subtitles to Video

Burn SRT/VTT captions into the picture or embed them as a soft track — entirely in your browser.

100% client-side · no upload

Video file (MP4, WebM, MOV…)

Subtitle file (.srt or .vtt)

Load a video and subtitle file to begin.

How to add subtitles to a video

Load your video file.
Load the matching SRT or VTT subtitle file.
Choose burn-in (always visible) or soft (toggle-able) mode.
Click Add subtitles and download the result.

Common use cases

Social media posts: Burn captions in so viewers watching with sound off can still follow along.
Accessibility: Add a toggle-able subtitle track to make video content reachable for deaf and hard-of-hearing audiences.
Multilingual videos: Embed a translated subtitle file alongside the original audio.
Tutorials: Reinforce spoken instructions with on-screen text for noisy or office environments.

Related tools: Video Trimmer · Video Compressor · Video Cropper · Video to MP4

よくある質問

What is the difference between burn-in and soft subtitles?: Burn-in renders the captions directly onto every video frame so they appear in any player — but they cannot be turned off. Soft subtitles are stored as a separate text track inside the MP4 and can be toggled on or off by the viewer in compatible players.
Which subtitle file formats are supported?: SRT is the most reliable and is recommended. VTT (WebVTT) is also accepted; ffmpeg converts it internally as needed. Make sure the file is plain text and saved with UTF-8 encoding.
Will burn-in re-encode the video?: Yes. Burning subtitles into the picture requires re-rendering every frame, so the video stream is re-encoded with the H.264 ultrafast preset. Soft mode stream-copies the video and is much faster.
Why are my subtitles not appearing in soft mode?: Soft subtitles need a player that supports MP4 mov_text — most modern players including VLC, mpv and YouTube uploads handle them. iOS Safari and QuickTime can be inconsistent; use burn-in if you target those.
Can I style the burnt-in subtitles?: This tool uses ffmpeg defaults — white text with a subtle outline at a readable size. For advanced styling (font, color, position), edit the SRT into an ASS file with explicit formatting before encoding.
Is anything uploaded to a server?: No. Both the video and the subtitle file are processed locally inside your browser via WebAssembly. Nothing leaves your device.

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