Check a caption file for lines that are too long, too fast, too short or overlapping, and fix them.
Caption files up to 2 MB: SRT, WebVTT, YouTube SBV or ASS.
Runs in your browser. Nothing is uploaded.
Open or paste a caption file to begin.
Studio keeps captions short enough to read and styles them for vertical clips.
Line length, number of lines, reading speed in characters a second, the shortest and longest time on screen, overlaps, and captions that end before they start. The default limits are the ones Netflix publishes for English: 42 characters a line, two lines, 20 characters a second for adults or 17 for children, and between 5/6 of a second and 7 seconds on screen.
It changes timing and line breaks, never words. An overlap is trimmed to end when the next caption starts. A caption with too many characters on one line is re-broken over two. A caption shown too briefly is held longer if there is room before the next one. A caption with too much text for its time needs a person: cut words, or split it in the caption editor.
A viewer has to read the caption and still see the picture. Past about 20 characters a second, most people cannot finish the line before it goes. Automatic captions fail this check most often, because they put a whole spoken sentence on screen at once.
No. It checks timing and layout. Only a person watching the video can check the words.
No. They are the style guide Netflix publishes for its own subtitles, widely used as a benchmark. The vertical-video option is our own suggestion for phone screens, not a published standard.
A CSV file with one row per caption: its times, characters a second, longest line and any problems. It opens in Excel or Google Sheets.
No. The check runs in your browser.
Fix caption text and timing line by line, with your video playing alongside.
Burn an SRT or WebVTT caption file into a video so the captions show on every platform.
Check whether a caption stays on screen long enough to read, against the 20 characters-a-second guideline.
Convert caption files between SRT, WebVTT, YouTube SBV and plain text, in your browser.
Convert the caption file, then inspect its cue times and text. A format conversion is not a spelling or synchronization repair.
Read the guide Guide · CaptionsMeasure whether the error is a constant delay or growing drift. Shift the whole file only when one offset fits the whole recording.
Read the guide Guide · CaptionsUse characters per second to find dense cues, then listen and rewrite the timing or line breaks without changing what was said.
Read the guideUpload the raw recording. Studio cuts the ums, retakes and long pauses, adds captions and makes short clips. 30 free minutes, no card.