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ConvertBox

Add subtitles to video

Burn SRT/VTT subtitles into your video or embed them as a soft track. Runs entirely in your browser β€” files never leave your device.

Video file

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Select a video

MP4, MOV, WebM β€” up to 50MB

Max file size: 50MB

or drag and drop Β· press Enter to browse

Subtitle file

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Select an .srt or .vtt

SRT or VTT format

Max file size: 5MB

or drag and drop Β· press Enter to browse

How to Use

  1. Pick the video file (max 50MB).
  2. Pick an SRT or VTT subtitle file.
  3. Choose between burn-in or soft subtitle mode.
  4. Click Add subtitles β€” your subbed MP4 will be downloaded.

All processing is done in your browser, and files are never sent to a server.

Frequently Asked Questions

Burn-in renders the subtitles into the video frames so they're always visible. Soft subtitles are a separate track that the viewer can turn on/off.
No. Encoding runs in your browser via FFmpeg WebAssembly. Your files never leave your device.
MP4 with H.264 is the most universally compatible format. The original codec is re-encoded for accuracy when burning subtitles in.