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Format

Web Video Text Tracks (WebVTT) Format

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Summary

Name
Web Video Text Tracks (WebVTT) Format
Identifiers
  • PUID: fmt/1454
  • MIME: text/vtt
Format type
Text (Structured)
Description
WebVTT files are used for captioning or subtitling video content. It is a standard created by the World Wide Web Consortium (W3C) for displaying timed text, and is linked to the HTML5 <track> element. The primary purpose of WebVTT files is to add text overlays to a video. Each time interval is specified in the format (HH:)mm:ss.xxx --> (HH:)mm:ss:xxx e.g. 00:00.000 --> 00:02.310 or 01:00:05.000 --> 01:00:07.000. The (HH:) is optional, but if included must have a minimum of 2 digits representing the hour (more than 2 digits may be used), and where both the minute (mm) and second (ss) parts must be between 00 and 59 inclusive.
Note
https://www.w3.org/TR/webvtt1/ https://developer.mozilla.org/en-US/docs/Web/API/WebVTT_API https://www.iana.org/assignments/media-types/text/vtt
File extensions
vtt
Source
LIBNOVA / LIBNOVA
Developed by
W3C / W3C
Supported by
W3C / W3C

Internal signatures

Web Video Text Tracks (WebVTT)

Note
Absolute from beginning of file, offset 0-4, magic bytes: WEBVTT {10-40} then a time stamp in the format xx:xx.xxx followed by --> {0-5} followed by xx:xx.xxx (where x is a number).

Byte sequences

Min Frag Length
Absolute from BOF
Offset
0
Max offset
4
Byte Sequence
574542565454{5-400}[30:35][30:39]3A[30:35][30:39]2E[30:39][30:39][30:39]202D2D3E20{0-5}[30:35][30:39]3A[30:35][30:39]2E[30:39][30:39][30:39]
Endianness
None

Changelog

  • Added in V110

    Release date
    14 March 2023

    Web Video Text Tracks (WebVTT) Format: Added links to documentation, expanded sig and des. Submitted by Digital Preservation Department, The National Archives (UK).

    Web Video Text Tracks (WebVTT) Format: Signature researched and samples provided by Digital Preservation Department, The National Archives (UK).

  • Updated in V99

    Release date
    19 November 2021

    Web Video Text Tracks (WebVTT) Format: Max-offset at beginning of file extended. Submitted by The Church of Jesus Christ and the Latter-day Saints.

  • Added in V98

    Release date
    27 October 2021

    Web Video Text Tracks (WebVTT) Format: Signature developed and samples provided by LIBNOVA.

    Web Video Text Tracks (WebVTT) Format: Full entry added. Submitted by LIBNOVA.