Check structure before upload
Subtitle platforms and video editors can reject files for small structural mistakes such as broken numbering, impossible durations, overlapping cues, or malformed timing. This checker parses the subtitle file and rebuilds a normalized output.
The report separates repaired structural problems from readability warnings, so you can download the fixed file and still decide whether long or fast-reading captions need human editing.
What the fixer changes automatically
The repair step renumbers cues, clamps invalid negative times, gives extremely short cues a safer minimum duration, and moves overlapping cues forward so the file is easier for uploaders and players to read.
It does not rewrite meaning, translate text, or guess missing audio context. The goal is a technically cleaner subtitle file that still leaves editorial decisions in your hands.
Review readability warnings
Long lines and high reading speed can be valid syntax but still hard for viewers to follow. The checker flags captions that may need shorter text, better line breaks, or more screen time.
Treat these warnings as review prompts rather than automatic failures. Dialogue-heavy scenes, names, URLs, and technical terms may require human judgment before you shorten or split a cue.
Keep a safe review workflow
Run the checker before uploading subtitles to a video platform, LMS, social channel, or accessibility review. It is especially useful after translation, OCR cleanup, AI transcription, or manual copy-and-paste edits.
Download the fixed file as a new working copy and keep the original subtitle nearby. Before publishing, preview the repaired captions against the video to confirm that structure fixes did not hide a deeper timing issue.