CAPTIONCHECK / SUBTITLE QUALITY REVIEW
Every line deserves
a little breathing room.
Catch overlaps. Check readability. Keep your words yours.
Free beta · local processing. No account or payment is required. Your inputs are processed in browser memory, not uploaded by this app. When served online, the hosting provider receives normal access logs for page and asset requests; this does not make a hosted visit anonymous. No app analytics or automatic saving.
Save and share carefully. SRT exports contain caption text and timing. Issue logs include filenames, timing and rule findings, but omit caption text. Downloads are ordinary unencrypted files. Closing or reloading loses unsaved work; clearing this tab does not delete previous downloads. Confirm downloads exist and review them before sharing.
Practical limits. UTF-8 SRT only; 5 MiB (5,242,880 bytes), 10,000 cues and 20,000 UTF-16 code units per caption. Checks are heuristics, not delivery-platform or accessibility certification. No transcription, translation or automatic correction. Review exported captions in the intended player. These are implementation limits, not paid quotas. Browser, download and print behavior can vary; this beta has not completed real-browser acceptance testing.
01 / BRING YOUR CAPTIONS
A quick check before delivery.
UTF-8 SRT · up to 5 MiB / 10,000 cues · strict format
Or paste SRT text
Import not applied
Your current captions and edits are unchanged. Fix the source and try again.
Review rules Set your own delivery thresholds
Defaults are starting points, not a platform specification. Characters are Unicode code points, including spaces and literal markup; line breaks do not count. These checks cannot assess meaning, caption accuracy or accessibility compliance.
02 / REVIEW WITH INTENTION
The subtitle desk
Select a row to review its text and timing. All changes are manual.
| Cue / timing | Caption | Readability | Findings | Review |
|---|
Your next clear caption starts here.
Open an SRT file or try the synthetic sample.
03 / MAKE A DELIBERATE CHANGE
Review cue
HH:MM:SS,mmm · hours 00–99 · comma milliseconds
Blank lines are cue separators, so they cannot appear inside a caption. Markup stays literal.
Keep the words. Clear the handoff.
SRT exports preserve cue numbers, Unicode and text line breaks.
No autosave or local storage. Export before closing. The original file is never overwritten.
Format, privacy & review limits
Strict UTF-8 SRT only: positive cue numbers (up to 9 digits), two-digit hours, comma milliseconds and exactly one space around “-->”. LF and CRLF line endings and an initial UTF-8 BOM are supported. Non-sequential numbers are flagged, not changed. A cue can contain up to 20,000 UTF-16 code units. Files are rejected as a whole on syntax errors; no malformed blocks are silently deleted.
Overlaps, zero/reversed durations, reading speed, line length and cue duration are review findings. Timing issues can still be exported after explicit confirmation. Manual edits affect only the selected cue. SRT output uses LF line endings without a BOM, preserves file order and does not automatically renumber cues.
No audio/video upload, transcription, AI, translation, waveform, autosync or player validation. Literal formatting tags count toward character limits; grapheme clusters may contain multiple code points. These heuristics are not accessibility certification or a replacement for watching captions in their intended player.
All scripts, fonts and artwork are bundled. No app analytics, content uploads, account, cloud sync, billing or persistence. Reloading or closing loses unsaved edits and custom thresholds. Issue logs are not encrypted and include filenames and timing information.