What is a .vtt file?
WebVTT (Web Video Text Tracks) · Video · W3C · 2010s
VTT (WebVTT) is the subtitle format of the web. HTML5 video uses it to show captions in the browser. It works much like SRT but starts with a WEBVTT line and can add styling and on-screen positioning.
What is a .vtt file used for?
WebVTT is the W3C standard for captions on HTML5 video, loaded through a <track> element so a browser can display subtitles without any plugin.
It is close to SRT but with a few differences: the file begins with the word WEBVTT, timestamps use a dot before the milliseconds (00:00:01.000) rather than a comma, and cues can carry styling and positioning.
Like SRT it is plain text, so you can open and edit it in any text editor. Many tools convert freely between SRT and VTT.
You meet VTT mainly on websites and streaming players; for offline video files, SRT is still the more common companion.
How to open a .vtt file
The .vtt format opens in the following apps, grouped by operating system. If one app does not work, try another from the same list.
Windows
- Any text editor (to edit)
- browsers via the <track> element
- VLC
macOS
- TextEdit (to edit)
- browsers
- VLC
Linux
- Any text editor
- browsers
- VLC / mpv
Web
- HTML5 video with <track src=...>
How to convert a .vtt file
You can convert a .vtt file to SRT using a conversion tool or the export menu of an app that opens it.
.vtt file signature (magic bytes)
Programs recognise a .vtt file by the bytes at the start of the file, not by its name. These are the signatures for VTT. For a full breakdown, see the VTT file signature page.
| Hex signature | Offset | Note |
|---|---|---|
| 57 45 42 56 54 54 | 0 | 'WEBVTT' header on the first line |
See the full magic-numbers reference for every format.
Frequently asked questions
What is a .vtt file?
VTT (WebVTT) is the subtitle format of the web. HTML5 video uses it to show captions in the browser. It works much like SRT but starts with a WEBVTT line and can add styling and on-screen positioning.
What is the difference between VTT and SRT?
They do the same job. VTT starts with a WEBVTT line, uses a dot before the milliseconds in timecodes, and supports styling and positioning, which suits HTML5 web video. SRT is simpler and more common for offline video files. Tools convert between them easily.
How do I open a VTT file?
Open it in any text editor to read or edit the captions. To see it working, it needs to be attached to an HTML5 video through a <track> element, or you can play it alongside a video in VLC.
Related formats
Sources
Details on this page were checked against authoritative references: