Does it handle mixed CJK and Latin text?

Yes. It can normalize the spacing between CJK and Latin characters and apply the right punctuation rules per script.

Is Smart Cleaner free?

Yes, completely free with no sign-up, no watermarks, and no upload. It runs in any modern browser.

Smart Subtitle Cleaner

Fast. Private. Perfect.

Language-aware subtitle normalization that detects CJK vs Latin text and applies the right punctuation, quote, and spacing rules.

Private & Secure

Blazing Fast

Free & Unlimited

Before

<i>(music playing)</i>
Hello...   world!!
Hello, world!
Hello, world!

After

Hello, world!
Hello, world!
Hello, world!

Drag & drop your subtitle file here

or click to browse

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

100% LocalNo UploadSecureInstant

How It Works

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

The Smart Cleaner auto-detects the dominant language of your subtitles.

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

Click Clean to apply the rules. Every change is previewed.

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.

Truly Unlimited

No file size limits. No daily limits. Completely free.

Works Everywhere

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

Smart Cleaning Rules

Auto-detects subtitle language: Chinese, Japanese, Korean, or English/Latin.

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 before and after with a diff of every change.

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

How is Smart Cleaner different from the regular Subtitle Cleaner?

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.

Does it upload my files to a server?

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

What formats are supported?

Input: SRT, VTT, ASS, SSA, LRC, SBV, TTML, SCC, STL, SMI. Output: SRT or VTT.

What languages does it detect?

It auto-detects Chinese, Japanese, Korean, and English/Latin scripts, and applies the appropriate normalization rules for each.

Can I choose which rules to apply?

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

Is Smart Cleaner destructive?

No. It previews every change before applying and you can undo the result.

Ready to convert your subtitles?

Language-aware subtitle normalization that detects CJK vs Latin text and applies the right punctuation, quote, and spacing rules.