.VTT File Format

Introduction

WebVTT, the Web Video Text Tracks format, is the subtitle and caption format of the web, specified by the W3C. A web page attaches a .vtt file to a video with the HTML <track> element, and the browser shows the cues at the right times. HLS streams also carry their subtitles as WebVTT.

WebVTT grew out of SRT and looks much like it, but it has a proper specification. It is always UTF-8, and it adds cue positioning, speaker names, styling with CSS and comments.

Structure

The file must begin with the word WEBVTT, optionally followed by a space and a title on the same line. After a blank line come blocks separated by blank lines. Most blocks are cues: an optional identifier line, a timing line, then the text. Times are written hours:minutes:seconds.milliseconds with a full stop, and the hours can be left out. Settings after the times, such as line, position, size and align, place the cue on screen.

The text can use the tags <b>, <i>, <u>, <v Speaker> for the voice speaking, and <c.class> for CSS styling. Other blocks are NOTE for comments, STYLE for CSS and REGION for named areas of the screen.

WEBVTT

NOTE The opening scene

intro-1
00:01.000 --> 00:03.500 line:85%
<v Anna>Where are we going?

00:04.000 --> 00:06.250
<v Ben><i>Somewhere we have never been.</i>

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