AscendLab
Tool guide

Subtitle Time Shifter Guide

Reference for shifting SRT or VTT subtitle timestamps when captions are early, late, or reused after trimming video.

Quick answer

Use Subtitle Time Shifter when captions are consistently early or late. Paste SRT or VTT text, choose a positive or negative offset, and review several points in the result.

What this tool does

The tool adjusts subtitle timestamps by the same offset. It is best for uniform sync problems, such as a caption track that starts 1.5 seconds too late after a video intro was trimmed.

Step-by-step use

  1. Keep a copy of the original caption file.
  2. Identify whether captions are early or late.
  3. Enter a positive offset to move captions later, or a negative offset to move them earlier.
  4. Apply the shift.
  5. Check the first, middle, and final captions against the video.

Example

If every caption appears about 2 seconds early, shift the subtitle file by +2 seconds. If the first captions are correct but later captions drift, this tool is not enough; the source timing likely needs segment-level correction.

Data handling and processing behavior

Processing is handled in the browser for this tool based on the current public implementation. Avoid entering sensitive transcript text unless you have reviewed the implementation and your own data handling requirements.

Assumptions and limits

The tool applies one offset to the entire file. It does not repair drift, missing cues, bad line breaks, or translation quality.

Common mistakes

Using one offset for drift. If timing is correct at the start and wrong at the end, the subtitle file may need retiming in an editor.

Forgetting trimmed intros. A removed 3-second intro usually means captions need to move earlier by 3 seconds.

Next steps

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