Kinesis Subtitle Lab

What Subtitle Lab does

Open a SubRip (.srt) or WebVTT (.vtt) file, or paste its text. Subtitle Lab reads every cue, lists what needs attention and lets you correct cues one by one. When you are done, download the file as SRT or VTT.

Nothing changes unless you ask for it. Checks only report; wrapping and clean-up run when you press Apply, and each step can be undone.

What the checks look for

• Errors break playback: unreadable timestamps, cues that end before they start, blank lines inside a cue, and a missing WEBVTT header.
• Warnings are worth a look: overlapping or out-of-order cues, empty cues, very short or long durations, long lines, too many lines and fast reading speed.
• Notes are housekeeping, such as stray spaces or SubRip timestamps written with a period.

Set the limits to your delivery spec under Limits. Reading speed counts the characters a viewer reads, spaces included and tags excluded, per second on screen.

Converting between SRT and VTT

Timing and text carry over exactly. SubRip has no header, comments, styles, regions or cue positions, so a WebVTT file loses those when saved as SRT; the output preview lists everything that will be left out before you download.

Ambiguous timestamps, such as 00:00:01,5, are never guessed. The cue is kept as it is and marked as an error for you to correct.

Your files stay on your computer

Subtitle Lab runs entirely in your browser. Files are read on your device and the page is not allowed to send data anywhere. Your limit and export preferences are remembered in this browser; subtitle text is not.

Keyboard: Ctrl+Z undoes, Ctrl+Shift+Z redoes, and Alt+↑/↓ moves between cues while editing.