Smart Subtitle Cleaner
Language-aware subtitle normalization for CJK and Latin scripts, with punctuation, quote, dash, and spacing rules.
Drag & drop your subtitle file here
Drag and drop subtitle files here or click to browse
Smart Cleaning Rules
Engineered for video editors and localization teams. Helps enforce common subtitle timing rules and formatting.
Smart Subtitle Cleaner Live Execution Demo
In-Memory Processing
File parsing, mutations, and time shifts for standard tools run in browser memory without sending subtitle files to our servers.
Millisecond Precision
Millisecond-accurate timecode parsing and arithmetic prevent synchronization drift across desktop and web players.
Fault-Tolerant Engine
Automatic multi-encoding detection and syntax sanitization gracefully handle malformed cues and unexpected linebreaks.
Who Needs Smart Cleaning?
Real-world scenarios across video post-production, course transcription, and global localization.
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.
How It Works
Streamlined end-to-end processing pipeline engineered for speed and precision.
Upload your subtitle file
SRT, VTT, ASS, SSA, LRC, SBV, TTML, SCC, STL, and SMI are supported.
Format Analysis
Choose Auto to detect the dominant script, or select a specific language for the cleaning rules.
Configuration
Toggle which normalization rules to apply (punctuation, quotes, dashes, spacing).
Processing
Click Clean to apply the rules and review the resulting text.
Verify & Export
Download the normalized subtitle file.
Why Choose AllSubConverter?
Client-Side Privacy
Standard tools run in your browser so standard files are not uploaded to our servers.
Fast Local Parsing
Optimized processing engine parses and converts files directly in your browser.
Generous Batches
Up to 50 MB per file, 200 files or 1 GB total per batch.
Universal Compatibility
Runs in modern browsers across Windows, macOS, Linux, iOS, and Android.
More Subtitle Tools
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.
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