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Converter Hub / Batch subtitle workflow

Batch Subtitle Sync

Apply a positive or negative millisecond offset to multiple SRT / VTT files and package the results in the browser.

Back to Converter HubJSZip Local batch sync

Synchronize subtitle timelines

Apply one millisecond offset and preserve or convert SRT, VTT and TXT output.

Batch progress0%

Features and usage guide

What is this tool for?

Drop multiple SRT / VTT files, apply one positive or negative millisecond offset, preserve or convert formats, and package results with JSZip.

3-step quick guide

  1. 1
    Select or drop multiple subtitle files and review the batch list.
  2. 2
    Enter a millisecond offset and choose an output format.
  3. 3
    Run batch sync, review each status and download the ZIP.

Privacy statement

Batch subtitle text and the ZIP stay in the browser; source files are not uploaded, overwritten or stored remotely.

There is no file-upload endpoint; practical speed depends on device performance and browser support.

Frequently asked questions

Are batch subtitles uploaded?

No. Each file is read, transformed and packaged locally in the browser.

How do positive and negative offsets work?

Positive values delay captions and negative values move them earlier; timestamps are clamped at 00:00:00.

Will source files be overwritten?

No. The output uses new filenames and a new ZIP; source files are never modified.