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Subtitle Sync Fixer

If every line is a little early or late, shift them all at once. If the gap grows over time (a different frame rate or cut), stretch the timing by matching two lines.

  • Nothing is uploaded
  • Free, no sign-up, no watermark
  • Works offline once loaded

How to use Subtitle Sync Fixer

  1. 1

    Add the subtitle file

    Drop an SRT, VTT or ASS file on the drop zone.

  2. 2

    Set the shift

    Type a positive Shift by value in milliseconds to make subtitles appear later, or negative to make them appear earlier.

  3. 3

    Fix frame rate drift if needed

    If the subtitles drift further out of sync over time, choose the matching Frame rate fix, such as 23.976 to 25 fps.

  4. 4

    Apply and download

    Press Apply, check the first and last lines, then Download in the same format.

Why use Aback Video for this

  • Shift every line

    Move the whole file earlier or later in one step, to the millisecond.

  • Frame rate fixes

    Common PAL and NTSC conversions correct subtitles that drift over a whole film.

  • Format kept

    An SRT stays an SRT, a VTT stays a VTT, with styling preserved.

  • Never uploaded

    The file is edited in your browser.

Frequently asked questions

How do I find the right offset?

Play the video and note when a line is spoken, then compare it with the line's start time in the file. The difference is your offset. 1 second is 1000 ms.

When do I need the frame rate fix?

When the first lines are in sync but the last ones are far off, the subtitles were timed for a version of the video with a different frame rate, typically 23.976 versus 25 fps.

What happens to lines that would start before zero?

They are clamped to start at zero, and lines that end before zero are removed.

Is my file uploaded?

No. The timing is changed in your browser.

Can I then burn the subtitles into my video?

Yes. Download the fixed file and use Burn Subtitles.

Does it work on a phone?

Yes. It is instant on any device.

Related tools

Subtitle Converter

Convert between SRT, VTT, ASS and plain text, instantly.

Burn Subtitles

Burn an SRT, VTT or ASS file into the picture with your own style.

Fix Audio Delay

Shift the sound earlier or later to fix lip-sync, without re-encoding the picture.

Add Text to Video

Put a title, caption or credit on a video, for all of it or part of it.

Add Logo or Watermark

Place your logo on a video with position, size and opacity controls.

Extract Subtitles

Save the subtitle tracks inside an MKV or MP4 as SRT, VTT or ASS files.

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