Frequently Asked Questions

📋 General Questions

What is Subconverter?

Subconverter is a free online platform that provides professional-grade subtitle tools. We offer conversion between formats (SRT, VTT, ASS, SSA, SUP, SUB/IDX), sync adjustment, encoding fixes, OCR extraction, and more. All tools work directly in your browser with no software installation required.

Is this tool really free?

Yes! All our tools are 100% free to use with no signup, registration, or credit card required. We support our service through non-intrusive ads. There are no hidden fees or premium tiers.

Do I need to create an account?

No! You can use all our tools instantly without creating an account. Simply upload your file, process it, and download the result. No email, no registration, no hassle.

What makes Subconverter different from other subtitle tools?

Subconverter stands out with:

No installation required - Everything works in your browser
100% free - No hidden costs or premium features
Advanced OCR - Extract text from image-based subtitles (SUP, SUB/IDX)
Batch processing - Convert multiple files at once
Privacy focused - Files auto-deleted after 1 hour
Format preservation - Maintains styling, colors, and positioning

📝 File Formats

Which subtitle formats are supported?

We support all major subtitle formats:

Text-based formats:

SRT (SubRip) - Most popular format
VTT (WebVTT) - Web standard format
ASS/SSA (Advanced SubStation) - With styling
DFXP/TTML - XML-based format
SBV (YouTube format)

Image-based formats:

SUP (PGS/Blu-ray subtitles)
SUB/IDX (VobSub/DVD subtitles)

Note: Image-based formats require OCR processing

What's the difference between SRT and VTT?

SRT (SubRip) is the most universal subtitle format, supported by virtually all media players. It contains timestamps and text only.

VTT (WebVTT) is the modern web standard format used by HTML5 video players. It supports additional features like positioning, styling, and metadata. Use VTT for web videos and SRT for local media players.

What is the maximum file size I can upload?

Maximum file size is 100MB per upload. This is sufficient for most subtitle files, including large SUP/SUB files from full-length Blu-ray movies.

🔧 Tool-Specific Questions

How accurate is the OCR for SUP/SUB+IDX conversion?

Our OCR engine (Tesseract 4.x with 130+ language support) provides high accuracy:

English: 95-99% accuracy for clean Blu-ray subtitles
European languages: 90-98% accuracy (German, French, Spanish, etc.)
Asian languages: 85-95% accuracy (depends on font quality)
Arabic/Hebrew: 90-95% accuracy with proper RTL handling

Tip: Results depend on image quality, font clarity, and correct language selection.

How long does SUP to SRT conversion take?

Processing time depends on subtitle length and image count:

Short files (500 images): 5-10 minutes
Average files (1000 images): 10-20 minutes
Long files (2000+ images): 30-60 minutes

You'll see real-time progress updates. You can close the tab and return later - your job continues processing.

Why does my SUP conversion fail or take very long?

Common causes:

Wrong language selected: If you select Arabic OCR for English text, processing will be 70x slower and produce gibberish. Use our auto-detect feature!
Corrupted SUP file: Make sure you extracted the file correctly from your Blu-ray.
Very large file: Files with 5000+ images may take over an hour. This is normal for 2-hour+ movies.

Pro tip: Our system auto-detects language from filename patterns like [eng], [deu], _fra_, etc. Use descriptive filenames!

What does the SRT Cleaner do?

The SRT Cleaner fixes common subtitle issues:

Removes advertising and credit text
Fixes malformed timestamps
Removes duplicate entries
Cleans up formatting tags

Perfect for cleaning up auto-generated or OCR-extracted subtitles.

🔒 Privacy & Security

Is my data safe and private?

Absolutely. We take your privacy seriously:

All uploads are encrypted in transit (HTTPS)
Files are stored temporarily with unique, unguessable URLs
Files are automatically deleted after 1 hour
We never read, share, or analyze your subtitle content
No tracking cookies or user profiling

How long are my files stored?

Uploaded files and converted results are automatically deleted after 1 hour. For long-running OCR jobs, files are retained until processing completes, then deleted 1 hour after completion.

Can other people access my files?

No. Each upload is assigned a cryptographically secure random URL (128-bit UUID). Without this exact URL, no one can access your files - not even by guessing.

⚙️ Technical Issues

Why is my upload failing?

Common causes and solutions:

File too large: Maximum 100MB. Compress or split your file.
Unsupported format: Check if your file format is supported.
Browser issue: Try a different browser (Chrome, Firefox recommended).
Network timeout: Check your internet connection and try again.

Which browsers are supported?

Subconverter works best on modern browsers:

✅ Chrome 90+ (recommended)
✅ Firefox 88+ (recommended)
✅ Safari 14+ (macOS)
✅ Edge 90+ (Chromium-based)
⚠️ Internet Explorer: Not supported

💰 Pricing & Limits

Is there really no paid version?

Correct! Subconverter is 100% free with no premium plans, subscriptions, or paid features. All tools are available to everyone without restrictions. We're supported by ads, which help keep the service free for all users.

Are there any usage limits or restrictions?

We have minimal fair-use limits to prevent abuse:

File size: 100MB maximum per upload
Rate limiting: Reasonable usage allowed (no bulk automation)

If you need higher limits for commercial use, please contact us.

How can I support Subconverter?

We appreciate your support! You can help by:

📢 Sharing Subconverter with others who need subtitle tools
⭐ Leaving feedback via our contact form
🔗 Linking to us from your website or social media
🛡️ Whitelisting us in your ad blocker (ads keep us free)