O **elemento HTML<track> **é usado como filho dos elementos de mídia<audio> e<video>. Ele permite que você especifique faixas de texto temporizadas (ou dados baseados em tempo), por exemplo, para lidar automaticamente com legendas. As faixas são formatadas emWebVTT format (arquivos.vtt) — Web Video Text Tracks orTimed Text Markup Language (TTML).

Experimente

<video controls src="/shared-assets/videos/friday.mp4">  <track    default    kind="captions"    srclang="en"    src="/shared-assets/misc/friday.vtt" />  Download the  <a href="/shared-assets/videos/friday.mp4">MP4</a>  video, and  <a href="/shared-assets/misc/friday.vtt">subtitles</a>.</video>

video {  width: 250px;}video::cue {  font-size: 1rem;}

Atributos

Este elemento inclui osatributos globais.

default

This attribute indicates that the track should be enabled unless the user's preferences indicate that another track is more appropriate. This may only be used on onetrack element per media element.

kind

How the text track is meant to be used. If omitted the default kind issubtitles. If the attribute is not present, it will use thesubtitles. If the attribute contains an invalid value, it will usemetadata. (Versions of Chrome earlier than 52 treated an invalid value assubtitles.) The following keywords are allowed:

• subtitles

  • Subtitles provide translation of content that cannot be understood by the viewer. For example dialogue or text that is not English in an English language film.
  • Subtitles may contain additional content, usually extra background information. For example the text at the beginning of the Star Wars films, or the date, time, and location of a scene.

• captions

  • Closed captions provide a transcription and possibly a translation of audio.
  • It may include important non-verbal information such as music cues or sound effects. It may indicate the cue's source (e.g. music, text, character).
  • Suitable for users who are deaf or when the sound is muted.

• descriptions

  • Textual description of the video content.
  • Suitable for users who are blind or where the video cannot be seen.

• chapters

  • Chapter titles are intended to be used when the user is navigating the media resource.

• metadata

  • Tracks used by scripts. Not visible to the user.

label

A user-readable title of the text track which is used by the browser when listing available text tracks.

src

Address of the track (.vtt file). Must be a valid URL. This attribute must be specified and its URL value must have the same origin as the document — unless the<audio> or<video> parent element of thetrack element has acrossorigin attribute.

srclang

Language of the track text data. It must be a validBCP 47 language tag. If thekind attribute is set tosubtitles, thensrclang must be defined.

Usage notes

The type of data thattrack adds to the media is set in thekind attribute, which can take values ofsubtitles,captions,descriptions,chapters ormetadata. The element points to a source file containing timed text that the browser exposes when the user requests additional data.

Amedia element cannot have more than onetrack with the samekind,srclang, andlabel.

Examples

<video controls poster="/images/sample.gif">  <source src="sample.mp4" type="video/mp4" />  <source src="sample.ogv" type="video/ogv" />  <track kind="captions" src="sampleCaptions.vtt" srclang="en" />  <track kind="descriptions" src="sampleDescriptions.vtt" srclang="en" />  <track kind="chapters" src="sampleChapters.vtt" srclang="en" />  <track kind="subtitles" src="sampleSubtitles_de.vtt" srclang="de" />  <track kind="subtitles" src="sampleSubtitles_en.vtt" srclang="en" />  <track kind="subtitles" src="sampleSubtitles_ja.vtt" srclang="ja" />  <track kind="subtitles" src="sampleSubtitles_oz.vtt" srclang="oz" />  <track kind="metadata" src="keyStage1.vtt" srclang="en" label="Key Stage 1" />  <track kind="metadata" src="keyStage2.vtt" srclang="en" label="Key Stage 2" />  <track kind="metadata" src="keyStage3.vtt" srclang="en" label="Key Stage 3" />  <!-- Fallback -->  ...</video>

Especificações

Compatibilidade com navegadores

See also

• WebVTT text track format