Add Japanese Subtitles to Video
ViralMint is a free Japanese subtitle generator — Whisper transcribes your video locally and adds accurate 日本語 captions with proper kanji and kana.
Free Japanese subtitle generator, powered by local Whisper
ViralMint adds Japanese (日本語) subtitles to any video using local Whisper transcription, which outputs natural mixed kanji-kana text rather than romaji. Paste a video and get word-level Japanese timestamps in seconds, then burn captions or export .srt/.ass. Because Japanese isn't space-delimited, ViralMint relies on Whisper's segment timing for caption breaks, which keeps phrasing readable. To localise an English video into Japanese, translate-and-dub transcribes the original locally, translates to Japanese, and re-times the subtitles — useful for reaching Japan's large, high-engagement YouTube and anime-adjacent audiences. Everything runs locally: no upload, no minute cap, no watermark.
How to add Japanese subtitles to a video
-
Open the caption tool
Launch ViralMint and open Tools → Captions. It accepts mp4, mov, mkv and webm.
-
Drop in your video
Local Whisper transcribes it into Japanese (日本語) with word-level timestamps — on your machine, nothing uploads. If the audio is another language, translate-and-dub can convert it to Japanese first.
-
Style or export
Burn word-by-word animated Japanese captions (viral / classic / bold), or export a standalone .srt / .ass file for any editor.
-
Render the mp4
ViralMint burns the Japanese subtitles in with FFmpeg and writes the final mp4 — original untouched, zero watermark.
Frequently Asked Questions
Does it output kanji or just romaji?
Proper Japanese — Whisper transcribes into natural mixed kanji and kana (hiragana/katakana), not romaji, so the subtitles read the way native viewers expect.
How are line breaks handled without spaces?
Japanese isn't space-delimited, so ViralMint uses Whisper's segment-level timing to break captions at natural phrase boundaries, keeping each on-screen line readable.
Can I translate an English video into Japanese?
Yes — translate-and-dub transcribes the English audio locally, translates to Japanese, and re-times the captions.