Free, instant, and entirely in your browser — your subtitle file is never uploaded.
MicroDVD counts frames, not seconds — this has to match the video.
WebVTT is SRT rebuilt for the web: the same cue structure, a WEBVTT header line, a dot instead of a comma before the milliseconds, and optional positioning settings after the timestamp. It is the only subtitle format HTML5 video natively understands.
SBV is YouTube's own caption format, and about as simple as SRT with one line less: no sequence number, and the two timestamps separated by a comma rather than an arrow.
This is the shape of a video changing homes. The VTT came from a web player — your own site, a course platform, an HLS stream — and the video is now going up on YouTube instead. Both formats are plain timed text, so the captions themselves survive untouched; what gets left behind is any positioning the VTT carried, which the web allows and YouTube's format does not. If the captions simply sat at the bottom of the frame, nothing is lost at all. Three things in a VTT have nowhere to go on the other side and are quietly discarded: the WEBVTT line that opens every such file, any NOTE comments the author left for themselves, and cue identifiers if the file names its cues. Inline markup goes too — an <i> around a whispered line will be flattened to plain words, because SBV has no notion of emphasis at all.
You want SBV because you are uploading to YouTube and want the format its own editor writes. It is worth knowing this is rarely necessary — YouTube accepts SRT quite happily — so choose SBV when a workflow or a tool specifically asks for it, not as a default.
Both sides carry the same thing — lines of text with a start and an end — so this is the cleanest conversion in the set. Nothing is approximated and nothing is thrown away; the timestamps are rewritten in the target's notation and the text goes across as it stands. What changes is compatibility: which players, platforms and browsers will accept the file you end up with.
No. The conversion runs in your browser using JavaScript — your VTT file is read from disk, converted in memory and handed back as a download. Nothing is transmitted, so there is nothing for us to store or delete. You can disconnect from the internet after this page loads and the conversion still works.
This is the shape of a video changing homes. The VTT came from a web player — your own site, a course platform, an HLS stream — and the video is now going up on YouTube instead. Both formats are plain timed text, so the captions themselves survive untouched; what gets left behind is any positioning the VTT carried, which the web allows and YouTube's format does not. If the captions simply sat at the bottom of the frame, nothing is lost at all. Three things in a VTT have nowhere to go on the other side and are quietly discarded: the WEBVTT line that opens every such file, any NOTE comments the author left for themselves, and cue identifiers if the file names its cues. Inline markup goes too — an <i> around a whispered line will be flattened to plain words, because SBV has no notion of emphasis at all.
The page checks before it converts. Subtitle formats are identified by what is inside the file rather than by the extension — which matters, because .sub alone is used by three unrelated formats. If you hand this page something that is not VTT, it says so and points you at the all-format converter instead of producing a broken file.