Merge two subtitle files into bilingual subtitles or one continuous file
This subtitle merger combines two subtitle files in one of two ways. Bilingual mode puts two languages on screen at the same time — your own language and one you are learning, or the original dialogue and a translation for a mixed audience. Join parts mode appends the second file after the first, for a film split into CD1 and CD2 or a lecture recorded in two halves.
The two files can be in different formats — SRT, VTT, ASS, SSA, SBV, TTML, MicroDVD, LRC or JSON — and the result can be saved as SRT, WebVTT, ASS, SSA, SBV, TTML, DFXP or JSON. Both files are processed in your browser and are never uploaded.
How to use the Subtitle Merger
- Choose the mode: Bilingual (two languages on screen) or Join parts (CD1 + CD2).
- Drop or paste the first file on the left and the second on the right. Each side shows the detected format and the number of cues.
- For bilingual subtitles choose a Layout, a Timing tolerance and a Second language style. For joined parts, type the exact Part 1 video length if you know it.
- Pick the Output format and check the merged result in the preview and the timing report.
- Press Download and load the file in your player like any other subtitle file.
Subtitle Merger features
Stacked dual subtitles
Lines from both languages are combined into single cues, with the second language in italics or yellow if you like, so even players that show one subtitle at a time display both.
Timing tolerance
Translations are rarely timed identically. Second-language start and end times within your tolerance (300 ms by default) snap to the first language’s, so you don’t get flickering fragments where lines change a few frames apart.
Top-and-bottom layout
Keep each language in its own cues: in SRT and VTT the second language is positioned at the top of the screen, and ASS output gets separate Top and Bottom styles you can restyle in any subtitle editor.
Exact CD1 + CD2 joins
Part 2 is shifted by the length of part 1 — the real video length you enter, such as 52:13.480, or the end of the last part-1 subtitle if you leave it empty — and every cue is renumbered.
Mixed formats and encodings
Merge an ASS file with an SRT, or a UTF-8 file with an old Windows-1252 one. The merged file is clean UTF-8.
Stacked or top and bottom?
Stacked works everywhere, including televisions, phones and web players that only show one cue at a time. Each cue holds the first language’s line or lines followed by the second language. Keep both short: about four lines is the limit before the picture gets crowded.
Top and bottom keeps the languages apart, which is easier to read and preserves each language’s own timing. It relies on the player honouring positions and showing overlapping cues; most desktop players do, but some televisions ignore positions. ASS output is the most dependable choice for this layout.
How the timing tolerance works
Suppose an English line runs from 00:00:01.000 to 00:00:03.200 and its Hindi translation from 00:00:01.080 to 00:00:03.150. Without a tolerance the merger would have to create three cues: 80 ms of English alone, then both languages, then 50 ms of English alone again. With the default 300 ms tolerance the Hindi times snap to the English ones and you get one clean cue. Bigger differences are kept, because they are usually real — one translation splitting a sentence differently, for example.
Joining CD1 and CD2 subtitles correctly
When a film was split in two, the second subtitle file starts again at 00:00:00. To use it with the joined video, every part-2 time must move forward by the running time of part 1 — the length of the video file, not the time of its last subtitle, which is usually a little earlier. Check the length in your player or with the Video Metadata Viewer and type it into Part 1 video length. If you also need to join the video files, use Merge Videos.
Subtitle Merger FAQ
How do I make dual-language subtitles?
Choose Bilingual, load a subtitle file for each language, pick Stacked and download the SRT. Load it in your player like any other subtitle file and both languages appear together.
Can I merge two SRT files into one?
Yes. Use Join parts to append one after the other with a time offset, or Bilingual to show both at the same time.
Do both subtitle files need the same format?
No. Each file is detected separately, so an ASS file and an SRT, or a VTT and an SBV, can be merged.
Why do the two languages flicker in my merged subtitles?
Their timings differ by a few frames, which creates very short cues. Increase the Timing tolerance, for example to 500 ms, so nearby boundaries are lined up.
What should I enter as the part 1 length?
The exact running time of the first video file, for example 52:13.480. Leaving it empty starts part 2 right after the last subtitle of part 1, which is close but usually slightly early.
Are my subtitle files uploaded?
No. Merging happens entirely in your browser and nothing is sent to a server.
Can I burn the merged subtitles into the video?
Yes. Download the merged file and use Burn Subtitles to draw both languages permanently onto the picture.