Media Doctor · Free tool
Check an SRT or WebVTT file for broken timestamps, overlapping or out-of-order cues, encoding problems and format errors. Then download a cleaned UTF-8 file without changing any timing.
Runs in your browser. Subtitle text stays on this device, and cleaned files are created locally.
Windows apps from SteveShines
Create a transcript or captions on your PC, without uploading your recordings.
Offline transcription for audio and video.
Cut video, remove silence and add captions.
Video downloader and local media toolkit.
Some subtitle problems are formatting: a comma instead of a period, a missing header, cue numbers out of sequence or a missing blank line. Those can be corrected without changing what viewers see or when they see it, and the cleaned file lists every change.
Timing problems are different. To fix an overlap or a cue that ends before it starts, someone has to decide the correct time while listening to the audio. The checker points you to the exact cues and leaves their times untouched, so it never shifts your subtitles out of sync.
If every line is early, late or slowly drifting, use the Subtitle Shifter to move or resync the whole file.
00:01:02,500). It is supported by most desktop players, TVs and editing apps.WEBVTT, uses periods in timestamps (00:01:02.500) and supports positioning and styling. It is the format web browsers use for the HTML video element.No. Files and pasted text are checked in your browser, and cleaned files are created on your device. SteveShines does not receive your subtitle text.
It fixes formatting, not timing. Overlapping cues, cues that end before they start and cues out of order are reported with their cue numbers, because correcting them requires deciding what the right time is. The cleaned file keeps every start and end time exactly as written. To move every line earlier or later, sync by the first and last line or change the frame rate, use the free Subtitle Shifter.
Yes. Choose the output format when you create the cleaned file. The list of changes shows anything the target format cannot store, such as WebVTT positioning or SRT font colors.
The file was saved or opened with the wrong text encoding. The checker detects files that are not valid UTF-8, UTF-16 files and signs of double encoding. Cleaned files are always saved as UTF-8.
A cue starts before the previous one ends, so players show both at the same time, usually stacked. It is sometimes intentional for two speakers, but often a timing mistake.
Browsers are strict about WebVTT. The file must start with WEBVTT, timestamps must use a period before the milliseconds (00:00:01.000, not 00:00:01,000), and minutes and seconds need two digits. The checker flags each of these.
No. The Subtitle Checker validates existing SRT and WebVTT files and does not transcribe audio.