What This Tool Is For
You have bilingual subtitles but only want one of the tracks — or the other way round, you want to split or merge the two tracks:
- Keep only the original track or only the translation track
- Split into two separate files: original and translation
- Merge two same-timeline bilingual entries into one two-line entry
- Change the format along the way (read ASS, export SRT, and so on)
How It Detects Bilingual Content
Dual-track bilingual subtitles come in two common forms, and the tool recognizes each one — without guessing the language: Form A (one entry, two lines) splits tracks by writing system — kana, hangul, hanzi, Latin and other systems, ten in all; two different systems mean bilingual, and whichever appears first counts as the original. A single system (a long Chinese line wrapped in two, for example) is treated as monolingual and kept as is. Form B (two separate entries with identical timing) splits tracks by position — the two entries at the same timestamp form a pair, the first one counts as the original, and combinations that share the Latin alphabet, like English-French or English-German, are separated correctly too. When no bilingual content is detected, the mode selector and the Start button are grayed out together with a clear notice, so it never force-splits into wrong results.
The Four Modes
Pick one of four in the “Which one do you want?” dropdown: Keep original only and Keep translation only each produce one file; Split into two produces an original file and a translation file, with filenames auto-tagged `.orig` / `.dst` to prevent overwrites; Merge into one two-line entry turns each pair into a bilingual entry — original on one line, translation on the other — while monolingual pairs are kept as is and no second line is invented. When you switch modes or output formats, existing content re-runs automatically — no need to click Start again.
Input and Output
Reads seven formats — SRT, VTT, ASS, SSA, SBV, LRC, TXT (file extension first, content sniffing as fallback) — and exports four: SRT, VTT, ASS, TXT. Any input-output combination works, so cross-format conversion happens along the way. ASS `\N` line breaks are restored to real line breaks, and effect tags are stripped on cross-format export.
Results and Export
Results are shown in full in a read-only text box, each file with entry count and total duration stats; the Download and Copy buttons take the file away directly. The results area is a preview — there is no editing of text or timing here. To make changes, export first, then use the matching tool.
FAQ
One entry has English on one line and French on the other — why won’t it split? Form A splits tracks by writing system, so two languages that share one system inside a single entry cannot be separated. Restructure it as Form B (two entries on the same timeline) and position-based splitting works.
Only one file in the download? “Keep original only”, “Keep translation only” and “Merge into one two-line entry” each produce a single file by design; only “Split into two” gives you two, tagged `.orig` / `.dst`.
Can I batch process? One file at a time; queues are not supported.
Does it upload my subtitles? No — parsing and export run entirely in your browser.
Related Guides
For the quick way to split two tracks see Splitting Bilingual Subtitles into Two Tracks; for how bilingual subtitles are made see Two Ways to Make Bilingual Subtitles; for machine translation use AI Subtitle Translation.