WebVTT Converter
FileFlip converts WebVTT files into 5 other formats entirely inside your browser, using FFmpeg compiled to WebAssembly. The WebVTT file is never uploaded to a server: it is read off your disk, converted on your own machine, and saved back by the browser. There is no file-size limit and no account to create.
How do I convert a WebVTT file?#
- Drop your WebVTT file onto the converter at the top of this page, or click it to pick one from your computer.
- Choose the format you want out of it. FileFlip downloads the engine that conversion needs, once, and your browser caches it.
- Conversion starts the moment you pick the format, and the result is yours to download. The work happens in this tab, so nothing is uploaded and nothing is queued.
Is it safe to convert WebVTT files online?#
Yes, because nothing is uploaded. FileFlip converts WebVTT files inside the browser tab you already have open, using WebAssembly builds of the same engines a desktop converter would install. Your file is read from your own disk into the page's memory, and no request carrying it is ever made.
You do not have to take that on trust. Open your browser's network panel, run a conversion, and you will see the engine come down and your file go nowhere. There is no upload, no server-side copy, no retention window, and no account tied to what you converted.
How FileFlip works lists every engine, its version and its download size, and shows how to check for yourself that nothing leaves your machine.
What happens to a WebVTT file#
FileFlip converts WebVTT into 5 formats with FFmpeg, all of it inside the browser tab. Each conversion below names the engine it uses, what it downloads, and exactly what that conversion keeps or drops.
| Category | Subtitles |
|---|---|
| File extension | .vtt |
| FileFlip support | Read and written |
| Conversions available | 5 |
| Engines | FFmpeg |
| Downloaded to your browser | 30.8 MB on the first conversion, then cached |
What is a WebVTT file?#
A VTT file is a WebVTT text track: a WEBVTT header followed by timed cues, each with a start and end timecode and one or more lines of text, optionally carrying position, size and CSS-style settings that place and format the text on screen.
Use WebVTT for subtitles served to an HTML5 <video> element, where the browser reads the track natively and honors its cue positioning and styling.
Convert WebVTT to SRT when the destination is a player or device outside the browser that only expects plain, unpositioned captions.
The WebVTT file format reference covers the specification, the programs that open one, and what each conversion keeps or drops.
WebVTT questions people ask#
What is a WebVTT file used for?
A WebVTT file supplies the captions or subtitles for an HTML5 video, loaded through the <track> element so the browser displays them without any extra plugin. It's the format browsers expect natively, the way SRT is the format most desktop players expect.
Does a browser play VTT files directly?
Yes. WebVTT is the W3C's caption format built specifically for HTML5 video, so any modern browser renders a .vtt track on its own once it's referenced by a <track> tag, including any cue positioning or styling the file specifies.
What's the difference between SRT and VTT?
WebVTT starts with a WEBVTT header and adds cue positioning, sizing and CSS-style formatting on top of the same start/end-timecode-plus-text structure SRT uses. Converting SRT to VTT is close to lossless; converting VTT to SRT drops any positioning or styling the cues carry.
Can WebVTT position captions anywhere on screen?
Yes. WebVTT cues accept line, position, size and alignment settings that place text at a specific spot in the video frame, rather than always at the bottom center. Region blocks add scrolling captions on top of that.
Does WebVTT timing break if the video frame rate changes?
No. WebVTT times cues in minutes:seconds.milliseconds against the clock, not against a frame count, so it keeps sync with the video regardless of its frame rate. Frame-based formats like MicroDVD's .sub are the ones that drift when the frame rate changes.