Free Online Subtitle Validator
Is your subtitle file not loading? Does your video player show an error message? TheSubAI Subtitle Validator scans your file for syntax errors, timing conflicts, and formatting issues that break playback. Use our Auto-fix feature to repair broken subtitles instantly.
How to Validate and Fix Subtitles?
Ensure your subtitles are error-free in 3 steps:
- Upload your file: Drag and drop your SRT, VTT, or ASS file.
- Scan for Errors: The tool will automatically check for common issues like overlapping times or broken HTML tags.
- Auto-Fix & Download: Check the "Auto-fix" boxes to repair the errors automatically, then download the clean file.
Common Subtitle Errors We Fix
Our tool detects the most common technical standards violations that cause subtitles to fail:
1. Overlapping Timestamps
The Problem: When a new subtitle line tries to appear before the previous one has finished. This confuses media players and causes flickering or missing text.
The Fix: We automatically adjust the end time of the previous line to prevent the collision.
2. Unclosed Formatting Tags
The Problem: If you open an italic tag <i> but forget to close it with </i>, the rest of your movie might stay in italics, or the file might not load at all.
The Fix: Our validator detects missing closing tags and inserts them automatically.
3. Duration & Length Checks
The Problem: Subtitles that are too short (e.g., 50ms) flash too fast to read. Subtitles that are too long cover the screen unnecessarily.
The Fix: You can set a minimum (e.g., 500ms) and maximum duration. We automatically extend or shorten lines to meet these standards.
Why Validate Your Subtitles?
- Player Compatibility: Strict players like Samsung TV, Sony Bravia, and iTunes will reject SRT files with even minor syntax errors.
- Professional Standards: Ensure your subtitles meet broadcast guidelines (no empty entries, proper spacing).
- Save Time: Instead of hunting for one missing bracket in a 1000-line file, let our AI find it in milliseconds.
Free Online Subtitle Validator - FAQ
Smart TVs are very strict. Common reasons include overlapping timestamps (two lines trying to show at once) or bad file encoding. Our Validator checks for overlaps, and our Encoder tool can fix the encoding.
It means you started a style (like Bold or Italic ) but didn't finish it. For example: Hello World. This is a syntax error. Our tool automatically adds the missing to fix it.
This happens when Line 1 ends at 00:01:05,000 but Line 2 starts at 00:01:04,500. The times clash. Our Auto-fix feature adjusts the timing so they play one after another smoothly.
Yes. Sometimes subtitle files contain numbered entries with no text (e.g., just "45" and a timestamp). These are useless and can cause player errors. Our tool detects and removes them.