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Smart Subtitle Cleaner

Fast. Private. Perfect.

Language-aware subtitle normalization for CJK and Latin scripts, with punctuation, quote, dash, and spacing rules.

Private & Secure
Blazing Fast
Free & Private

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SRT, VTT, ASS, SSA, LRC, SBV, TTML, SCC, STL, SMI, TXT, JSON

100% LocalNo UploadSecureInstant

How It Works

1

Upload your subtitle file. SRT, VTT, ASS, SSA, LRC, SBV, TTML, SCC, STL, and SMI are supported.

2

Choose Auto to detect the dominant script, or select a specific language for the cleaning rules.

3

Toggle which normalization rules to apply (punctuation, quotes, dashes, spacing).

4

Click Clean to apply the rules and review the resulting text.

5

Download the normalized subtitle file.

Why Choose AllSubConverter?

Your Privacy Matters

Everything runs in your browser. Your files are never uploaded.

Lightning Fast

Optimized processing engine converts files in seconds.

Free & Local

Each file can be up to 50 MB. Batches can contain up to 200 files or 1 GB total.

Works Everywhere

Works on Windows, Mac, Linux, iOS, Android - any modern browser.

Smart Cleaning Rules

Auto-detects Japanese, Korean, Chinese, or Latin text, or select English, Chinese, Japanese, Korean, Spanish, French, or German.
Normalize CJK punctuation: full-width to half-width and vice versa where appropriate.
Fix smart quotes and straight quotes for consistent typography.
Normalize ellipsis characters and dash styles.
Remove extra spacing between CJK and Latin characters.
Strip redundant whitespace and fix line breaks.
Preview the normalized output before downloading it.
100% browser-based - no file uploads, fully private.

Who Needs Smart Cleaning?

CJK Subtitle Normalization

Normalize mixed full-width and half-width punctuation in Chinese, Japanese, and Korean subtitles for consistent display.

Fansub & Translation Teams

Standardize punctuation and quote styles across subtitle files from different translators.

Broadcast Delivery

Ensure subtitle typography meets platform style guides before delivery.

OCR Cleanup

Fix inconsistent punctuation and spacing introduced by OCR extraction from images or PDFs.

E-Learning Content

Produce clean, consistent subtitles for online courses with proper punctuation and spacing.

Multilingual Libraries

Normalize mixed-language subtitle files so CJK and Latin text render consistently.

Frequently Asked Questions

The regular cleaner removes HTML tags, ASS overrides, and hearing-impaired annotations. Smart Cleaner focuses on language-aware normalization: CJK punctuation, smart quotes, dash styles, and CJK/Latin spacing. They complement each other.

No. All cleaning happens entirely in your browser. Your subtitle files never leave your device.

Input: SRT, VTT, ASS, SSA, LRC, SBV, TTML, SCC, STL, SMI. Output preserves SRT, VTT, ASS/SSA, LRC, TXT, and TTML when reliable round-tripping is available. SCC, STL, SMI, SBV, and files that cannot be round-tripped fall back to SRT.

Auto-detection distinguishes Japanese, Korean, Chinese, and Latin text. English, Spanish, French, and German use the general Latin normalization rules.

Yes. Each normalization rule is an independent toggle. You can apply only punctuation fixes, only quote normalization, or any combination.

No. Review the normalized output before downloading it; the original file is not modified in place.

Ready to convert your subtitles?

Language-aware subtitle normalization for CJK and Latin scripts, with punctuation, quote, dash, and spacing rules.