View source for Using the TextTrack API to provide captions dynamically

[[Category:HTML5 Techniques]]
[[Category:Scripting Techniques]]

[[Category:Technique In Development]]

== Status ==
* New technique.

== Applicability ==
* HTML5 and client side scripting

== WCAG references ==
* media-equiv-captions: [http://www.w3.org/TR/WCAG20/#media-equiv-captions SC 1.2.2 Captions(Prerecorded)] (sufficient)
* media-equiv-captions: [http://www.w3.org/TR/WCAG20/#media-equiv-real-time-captions SC 1.2.4 Captions(Live)] (sufficient)

== User Agent and Assistive Technology Support Notes ==

* March 2012: [http://ie.microsoft.com/testdrive/Graphics/VideoCaptions/ Internet Explorer 10 Platform Preview 4 includes TTML and WebVTT <code>track</code> caption support.]

== Description ==

The objective of this technique is to use the HTML5 timed text tracks API to manupluate the list of pending text tracks for a video media element. Caption timed text tracks contain transcription or translation of the dialogue, sound effects, relevant musical cues, and other relevant audio information, suitable for when sound is unavailable or not clearly audible.

== Examples==
==Example 1==
Live caption cue handling.
<pre>
var stream = new Video('stream.webm');
var captions = stream.addTextTrack('captions', 'live captions', 'en-US');

// as caption cues come in, add them to the track for display
stream.addCue(new TextTrackCue('1', 12.783, 14.612, 'Mum, give me the
butter.'));
stream.addCue(new TextTrackCue('2', 14.612, 16.091, 'I am waiting for
the magic word!'));

</pre>

== Resources ==

* [http://www.w3.org/html/wg/drafts/html/CR/embedded-content-0.html#timed-text-tracks HTML5, 4.8.10.12 Timed text tracks]
* [http://www.whatwg.org/specs/web-apps/current-work/#timed-text-tracks HTML Living Standard, 4.7.10.12 Timed text tracks]

=== Related Techniques ===

* [http://www.w3.org/TR/WCAG20-TECHS/G87 G87: Providing closed captions]
* [[Using the track element to provide captions]]

== Tests ==

=== Procedure ===

#

=== Expected Results ===

*