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Dual Subtitle Merger
Merge two subtitle files (two languages) into one, top and bottom in ASS or stacked in SRT.
Free, no uploads, no sign-up. Runs 100% in your browser.
How Dual Subtitle Merger works
Both files are parsed in your browser. ASS output keeps each track with its own timing, colour and position. SRT and VTT output slice time where the two tracks differ and stack the lines, so every player can show both.
Input: SRT, VTT, ASS, SBV, LRC. Output: ASS, SRT, VTT.
How to use Dual Subtitle Merger
- Add the main subtitle file.
- Add the second language file.
- Pick ASS for top and bottom, or SRT for stacked lines.
- Download the merged file.
Tips
- Nothing is uploaded. Your files stay in this browser tab.
Dual Subtitle Merger FAQ
- Are my files uploaded?
- No. This tool runs entirely in your browser tab. Files are read from your disk into memory and the result is generated locally.
- Is it free? Are there limits or watermarks?
- Free and open source (MIT). There are no file-size caps, daily quotas, accounts or watermarks.
- Does it work offline?
- Yes, once the page (and any engine it needs) has loaded, it keeps working without a connection thanks to the service worker cache.
Related tools
- Subtitle Converter: Convert between SRT, VTT, ASS, SSA, SBV, SUB, LRC, SAMI, TTML, JSON and CSV in bulk.
- Subtitle Shift and Sync: Fix out-of-sync subtitles: shift all lines, correct frame rate drift, or line up two points.
- Subtitle Translator: Translate SRT, VTT or ASS files into 50+ languages on your device, keeping every timestamp.
- Subtitle Editor: Create and edit subtitles against a video preview. Set times from the player, split lines, save SRT, VTT or ASS.