ByteScope

Subtitle Translate

Translate a YouTube transcript or an SRT/VTT file in this tab — bilingual output, nothing uploaded.

Your files never leave your browser — all processing is local.

Drop an SRT/VTT file, paste subtitle text, or paste a YouTube transcript you copied. Translation runs in this tab.

Drop a subtitle file

SRT, VTT, ASS, SBV, LRC — or click to browse

Version and platform facts

Translator and Language Detector: desktop Chrome 138+. Mobile Chrome is ✗ on every row.

APIChromeChrome AndroidEdgeFirefoxSafari
TranslatorChrome 138+ stable. Desktop only.YesNoUntestedNoNo
Language DetectorChrome 138+ stable. Desktop only.YesNoUntestedNoNo

Translator language packs are small. Gemini Nano (Prompt / Summarizer) is a much larger download and is not used here.

This browser, right now

  • Translator …
  • LanguageDetector …

About this tool

A subtitle file does not need a cloud quota. Drop SRT or VTT (or ASS / SBV / LRC), paste the text, or paste a YouTube transcript you copied yourself. Chrome's on-device Translator API then walks the file cue by cue. Language packs download on demand. There is no account, no word limit from us, and the file never leaves this tab. Download translation-only or bilingual SRT/VTT when it is done.

How to copy a YouTube transcript

Open the video → expand the description → tap Show transcript → select all and copy → paste it into the YouTube tab here. Turn timestamps on before you copy; without them this page cannot rebuild cue times. This is the only legal path: the page will not fetch captions from a YouTube URL (CORS, bot detection, and YouTube's terms all forbid that). The same steps work for Translate YouTube subtitles searches — you bring the text, we restore the timestamps.

What this browser has to ship

Translator and Language Detector are Chrome 138+ on desktop. Mobile Chrome is a hard no. Firefox and Safari do not ship the APIs. Edge is Chromium and untested here. If this browser cannot translate, the matrix, the YouTube steps, the about, and the FAQ still render. Parse and validation run everywhere; only the translate button needs the APIs.

Frequently asked questions

Is my subtitle file uploaded?

No. Parsing, language detection and translation all run in this tab. The only download is a Translator language pack the first time this machine needs that pair, and your cues are not attached to that request.

How do I translate YouTube subtitles here?

On the video: expand the description, open Show transcript, copy the text (with timestamps), and paste it into the YouTube tab. We parse the timestamps back into cues. Paste a youtube.com URL and nothing happens — that fetch is blocked on purpose.

The paste has no times / cues overlap. What now?

If there are no timestamps, YouTube probably hid them — open the transcript menu and turn timestamps on, then copy again. Overlaps and zero-length cues are reported after parse (a pasted transcript can create those). They do not block translation; fix them in Subtitle Sync afterwards if a player chokes.

Which browsers can actually translate?

Desktop Chrome 138+ with Translator. Mobile Chrome, Firefox and Safari cannot. Edge may work as Chromium but is marked untested until someone measures it. The table stays on the page even when this browser cannot run the tool.

Can I stop a long file and continue later?

Yes. Abort stops at the next cue. Resume feeds the partial translations back in so finished cues are not sent again. Failed batches are listed with the cue range they covered. Output can be translation-only or bilingual (translation on top, or original on top).

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