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<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en">
<head>
<meta charset="UTF-8" />
<meta name="viewport" content="width=device-width, initial-scale=1" />
<title>Understanding Success Criterion 1.2.8: Media Alternative (Prerecorded) | WAI | W3C</title>
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<link rel="stylesheet" href="base.css" />
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<div class="default-grid nav-container nav-page-specific">
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<ul>
<li class="nav__item"><a href=".">
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<li class="nav__item"><a href="time-based-media">
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<div class="default-grid with-gap leftcol">
<aside class="box nav-hack sidebar standalone-resource__sidebar ">
<nav>
<header class="box-h ">Page Contents</header>
<div class="box-i">
<ul>
<li><a href="#brief">In Brief</a></li>
<li><a href="#intent">Intent</a></li>
<li><a href="#benefits">Benefits</a></li>
<li><a href="#examples">Examples</a></li>
<li><a href="#resources">Related Resources</a></li>
<li><a href="#techniques">Techniques</a></li>
<li><a href="#key-terms">Key Terms</a></li>
<li><a href="#test-rules">Test Rules</a></li>
</ul>
</div>
</nav>
</aside>
<main id="main" class="standalone-resource__main">
<h1><span class="standalone-resource__type-of-guidance">Understanding
SC 1.2.8:</span>Media Alternative (Prerecorded) (Level AAA)
</h1>
<aside class="box">
<header class="box-h box-h-icon">Success Criterion (SC) </header>
<div class="box-i">
<p>An <a href="#dfn-alternative-for-time-based-media">alternative for time-based media</a> is provided for all <a href="#dfn-prerecorded">prerecorded</a>
<a href="#dfn-synchronized-media">synchronized media</a> and for all prerecorded <a href="#dfn-video-only">video-only</a> media.
</p>
</div>
</aside>
<div class="excol-all"></div>
<section id="brief">
<h2>In Brief</h2>
<dl>
<dt>Goal</dt>
<dd>Precorded videos can be understood by more people.</dd>
<dt>What to do</dt>
<dd>Provide a text equivalent for all content in videos.</dd>
<dt>Why it's important</dt>
<dd>More people, including those who are deaf-blind, can better understand the content
at their own pace.
</dd>
</dl>
</section>
<section id="intent">
<h2>Intent</h2>
<p>The intent of this Success Criterion is to make audio visual material available to
individuals whose vision is too poor to reliably read
<a href="#dfn-captions">captions</a> and whose hearing is too poor to reliably hear dialogue and
<a href="#dfn-audio-description">audio description</a>. This is done by providing an alternative for time-based media.
</p>
<p>This approach involves providing all of the information in the synchronized media
(both visual and auditory) in text form. An alternative for time-based media provides
a running description of all that is going on in the synchronized media content. The
alternative for time-based media reads something like a book. Unlike audio description,
the description of the video portion is not constrained to just the pauses in the
existing dialogue. Full descriptions are provided of all visual information, including
visual context, actions and expressions of actors, and any other visual material.
In addition, non-speech sounds (laughter, off-screen voices, etc.) are described,
and transcripts of all dialogue are included. The sequence of descriptions and dialogue
transcripts is the same as the sequence in the synchronized media itself. As a result,
the alternative for time-based media can provide a much more complete representation
of the synchronized media content than audio description alone.
</p>
<p>If there is any interaction as part of the synchronized media presentation (e.g.,
"press now to answer the question") then the alternative for time-based media would
provide hyperlinks or whatever is needed to provide parallel functionality.
</p>
<p>Individuals whose vision is too poor to reliably read captions and whose hearing is
too poor to reliably hear dialogue can access the alternative for time-based media
by using a refreshable braille display.
</p>
<div class="note">
<p class="note-title marker">Note</p>
<div>
<p>
For 1.2.3, 1.2.5, and 1.2.7, if all of the information in the video track is already
provided in the audio track, no audio description is necessary.
</p>
<p>
1.2.3, 1.2.5, and 1.2.8 overlap somewhat with each other. This is to give the author
some choice at the minimum conformance level, and to provide additional requirements
at higher levels. At Level A in Success Criterion 1.2.3, authors do have the choice
of providing either an audio description or a full text alternative. If they wish
to conform at Level AA, under Success Criterion 1.2.5 authors must provide an audio
description - a requirement already met if they chose that alternative for 1.2.3,
otherwise an additional requirement. At Level AAA under Success Criterion 1.2.8 they
must provide an extended text description. This is an additional requirement if both
1.2.3 and 1.2.5 were met by providing an audio description only. If 1.2.3 was met,
however, by providing a text description, and the 1.2.5 requirement for an audio description
was met, then 1.2.8 does not add new requirements.
</p>
</div>
</div>
</section>
<section id="benefits">
<h2>Benefits</h2>
<ul>
<li>People who are deaf-blind, who cannot see well or at all, and who also cannot hear
well or at all can get
access to information in audio-visual presentations.
</li>
</ul>
</section>
<section id="examples">
<h2>Examples</h2>
<dl>
<dt>Example 1. alternative for time-based media for a training video</dt>
<dd>A community center purchases a Training video for use by its clients and puts it on
the center's intranet. The video involves explaining use of a new technology and has
a person talking and showing things at the same time. The community center provides
an alternative for time-based media that all clients, including those who can neither
see the demonstrations nor hear the explanations in the synchronized media, can use
to better understand what is being presented.
</dd>
</dl>
</section>
<section id="resources">
<h2>Related Resources</h2>
<p>Resources are for information purposes only, no endorsement implied.</p>
<ul>
<li>
<a href="http://www.uiaccess.com/transcripts/transcript_services.html">uiAccess list of transcription services</a>
</li>
<li>
<a href="http://www.uiaccess.com/transcripts/transcripts_on_the_web.html">Transcripts on the Web: Getting people to your podcasts and videos</a>
</li>
</ul>
</section>
<section id="techniques">
<h2>Techniques</h2>
<p>Each numbered item in this section represents a technique or combination of techniques
that the WCAG Working Group deems sufficient for meeting this Success Criterion. However,
it is not necessary to use these particular techniques. For information on using other
techniques, see <a href="understanding-techniques">Understanding Techniques for WCAG Success Criteria</a>, particularly the "Other Techniques" section.
</p>
<section id="sufficient">
<h3>Sufficient Techniques</h3>
<p>Select the situation below that matches your content. Each situation includes techniques
or combinations of techniques that are known and documented to be sufficient for that
situation.
</p>
<section class="situation" id="media-alternative-prerecorded-situation-0">
<h4>Situation A: If the content is prerecorded synchronized media:</h4>
<ul>
<li>
<p>
<a class="general" href="https://w3c.github.io/wcag/techniques/general/G69">G69: Providing an alternative for time based media</a> using one of the following techniques
</p>
<ul>
<li>
<a class="general" href="https://w3c.github.io/wcag/techniques/general/G58">G58: Placing a link to the alternative for time-based media immediately next to the non-text
content</a>
</li>
</ul>
</li>
<li>
<p>Linking to the alternative for time-based media using one of the following techniques
</p>
<ul>
<li>
<a class="html" href="https://w3c.github.io/wcag/techniques/html/H53">H53: Using the body of the object element</a>
</li>
</ul>
</li>
</ul>
</section>
<section class="situation" id="media-alternative-prerecorded-situation-1">
<h4>Situation B: If the content is prerecorded video-only:</h4>
<ul>
<li>
<a class="general" href="https://w3c.github.io/wcag/techniques/general/G159">G159: Providing an alternative for time-based media for video-only content</a>
</li>
</ul>
</section>
</section>
<section id="failure">
<h3>Failures</h3>
<p>The following are common mistakes that are considered failures of this Success Criterion
by the WCAG Working Group.
</p>
<ul>
<li>
<a class="failure" href="https://w3c.github.io/wcag/techniques/failures/F74">F74: Failure of Success Criterion 1.2.2 and 1.2.8 due to not labeling a synchronized media
alternative to text as an alternative</a>
</li>
</ul>
</section>
</section>
<section id="key-terms">
<details>
<summary>
<h2>Key Terms</h2>
</summary>
<dt id="dfn-alternative-for-time-based-media">alternative for time-based media</dt>
<dd>
<definition xmlns="">
<p xmlns="http://www.w3.org/1999/xhtml">document including correctly sequenced text descriptions of time-based visual and
auditory information and providing a means for achieving the outcomes of any time-based
interaction
</p>
<div xmlns="http://www.w3.org/1999/xhtml" class="note">
<p class="note-title marker">Note</p>
<p>A screenplay used to create the synchronized media content would meet this definition
only if it was corrected to accurately represent the final synchronized media after
editing.
</p>
</div>
</definition>
</dd>
<dt id="dfn-ascii-art">ascii art</dt>
<dd>
<definition xmlns="">
<p xmlns="http://www.w3.org/1999/xhtml">picture created by a spatial arrangement of characters or glyphs (typically from the
95 printable characters defined by ASCII)
</p>
</definition>
</dd>
<dt id="dfn-assistive-technology">assistive technology</dt>
<dd>
<definition xmlns="">
<p xmlns="http://www.w3.org/1999/xhtml">hardware and/or software that acts as a <a href="#dfn-user-agent">user agent</a>, or along with a mainstream user agent, to provide functionality to meet the requirements
of users with disabilities that go beyond those offered by mainstream user agents
</p>
<div xmlns="http://www.w3.org/1999/xhtml" class="note">
<p class="note-title marker">Note</p>
<p>Functionality provided by assistive technology includes alternative presentations
(e.g., as synthesized speech or magnified content), alternative input methods (e.g.,
voice), additional navigation or orientation mechanisms, and content transformations
(e.g., to make tables more accessible).
</p>
</div>
<div xmlns="http://www.w3.org/1999/xhtml" class="note">
<p class="note-title marker">Note</p>
<p>Assistive technologies often communicate data and messages with mainstream user agents
by using and monitoring APIs.
</p>
</div>
<div xmlns="http://www.w3.org/1999/xhtml" class="note">
<p class="note-title marker">Note</p>
<p>The distinction between mainstream user agents and assistive technologies is not absolute.
Many mainstream user agents provide some features to assist individuals with disabilities.
The basic difference is that mainstream user agents target broad and diverse audiences
that usually include people with and without disabilities. Assistive technologies
target narrowly defined populations of users with specific disabilities. The assistance
provided by an assistive technology is more specific and appropriate to the needs
of its target users. The mainstream user agent may provide important functionality
to assistive technologies like retrieving Web content from program objects or parsing
markup into identifiable bundles.
</p>
</div>
<aside xmlns="http://www.w3.org/1999/xhtml" class="example">
<p>Assistive technologies that are important in the context of this document include
the following:
</p>
<ul>
<li>screen magnifiers, and other visual reading assistants, which are used by people with
visual, perceptual and physical print disabilities to change text font, size, spacing,
color, synchronization with speech, etc. in order to improve the visual readability
of rendered text and images;
</li>
<li>screen readers, which are used by people who are blind to read textual information
through synthesized speech or braille;
</li>
<li>text-to-speech software, which is used by some people with cognitive, language, and
learning disabilities to convert text into synthetic speech;
</li>
<li>speech recognition software, which may be used by people who have some physical disabilities;</li>
<li>alternative keyboards, which are used by people with certain physical disabilities
to simulate the keyboard (including alternate keyboards that use head pointers, single
switches, sip/puff and other special input devices.);
</li>
<li>alternative pointing devices, which are used by people with certain physical disabilities
to simulate mouse pointing and button activations.
</li>
</ul>
</aside>
</definition>
</dd>
<dt id="dfn-audio">audio</dt>
<dd>
<definition xmlns="">
<p xmlns="http://www.w3.org/1999/xhtml">the technology of sound reproduction</p>
<div xmlns="http://www.w3.org/1999/xhtml" class="note">
<p class="note-title marker">Note</p>
<p>Audio can be created synthetically (including speech synthesis), recorded from real
world sounds, or both.
</p>
</div>
</definition>
</dd>
<dt id="dfn-audio-description">audio description</dt>
<dd>
<definition xmlns="">
<p xmlns="http://www.w3.org/1999/xhtml">narration added to the soundtrack to describe important visual details that cannot
be understood from the main soundtrack alone
</p>
<div xmlns="http://www.w3.org/1999/xhtml" class="note">
<p class="note-title marker">Note</p>
<p>Audio description of <a href="#dfn-video">video</a> provides information about actions, characters, scene changes, on-screen text, and
other visual content.
</p>
</div>
<div xmlns="http://www.w3.org/1999/xhtml" class="note">
<p class="note-title marker">Note</p>
<p>In standard audio description, narration is added during existing pauses in dialogue.
(See also <a href="#dfn-extended-audio-description">extended audio description</a>.)
</p>
</div>
<div xmlns="http://www.w3.org/1999/xhtml" class="note">
<p class="note-title marker">Note</p>
<p>Where all of the <a href="#dfn-video">video</a> information is already provided in existing <a href="#dfn-audio">audio</a>, no additional audio description is necessary.
</p>
</div>
<div xmlns="http://www.w3.org/1999/xhtml" class="note">
<p class="note-title marker">Note</p>
<p>Also called "video description" and "descriptive narration."</p>
</div>
</definition>
</dd>
<dt id="dfn-captions">captions</dt>
<dd>
<definition xmlns="">
<p xmlns="http://www.w3.org/1999/xhtml">synchronized visual and/or <a href="#dfn-text-alternative">text alternative</a> for both speech and non-speech audio information needed to understand the media content
</p>
<div xmlns="http://www.w3.org/1999/xhtml" class="note">
<p class="note-title marker">Note</p>
<p>Captions are similar to dialogue-only subtitles except captions convey not only the
content of spoken dialogue, but also equivalents for non-dialogue audio information
needed to understand the program content, including sound effects, music, laughter,
speaker identification and location.
</p>
</div>
<div xmlns="http://www.w3.org/1999/xhtml" class="note">
<p class="note-title marker">Note</p>
<p>Closed Captions are equivalents that can be turned on and off with some players.</p>
</div>
<div xmlns="http://www.w3.org/1999/xhtml" class="note">
<p class="note-title marker">Note</p>
<p>Open Captions are any captions that cannot be turned off. For example, if the captions
are visual equivalent <a href="#dfn-image-of-text">images of text</a> embedded in <a href="#dfn-video">video</a>.
</p>
</div>
<div xmlns="http://www.w3.org/1999/xhtml" class="note">
<p class="note-title marker">Note</p>
<p>Captions should not obscure or obstruct relevant information in the video.</p>
</div>
<div xmlns="http://www.w3.org/1999/xhtml" class="note">
<p class="note-title marker">Note</p>
<p>In some countries, captions are called subtitles.</p>
</div>
<div xmlns="http://www.w3.org/1999/xhtml" class="note">
<p class="note-title marker">Note</p>
<p>
<a href="#dfn-audio-description">Audio descriptions</a> can be, but do not need to be, captioned since they are descriptions of information
that is already presented visually.
</p>
</div>
</definition>
</dd>
<dt id="dfn-extended-audio-description">extended audio description</dt>
<dd>
<definition xmlns="">
<p xmlns="http://www.w3.org/1999/xhtml">audio description that is added to an audiovisual presentation by pausing the <a href="#dfn-video">video</a> so that there is time to add additional description
</p>
<div xmlns="http://www.w3.org/1999/xhtml" class="note">
<p class="note-title marker">Note</p>
<p>This technique is only used when the sense of the <a href="#dfn-video">video</a> would be lost without the additional <a href="#dfn-audio-description">audio description</a> and the pauses between dialogue/narration are too short.
</p>
</div>
</definition>
</dd>
<dt id="dfn-human-language">human language</dt>
<dd>
<definition xmlns="">
<p xmlns="http://www.w3.org/1999/xhtml">language that is spoken, written or signed (through visual or tactile means) to communicate
with humans
</p>
<div xmlns="http://www.w3.org/1999/xhtml" class="note">
<p class="note-title marker">Note</p>
<p>See also <a href="#dfn-sign-language">sign language</a>.
</p>
</div>
</definition>
</dd>
<dt id="dfn-image-of-text">image of text</dt>
<dd>
<definition xmlns="">
<p xmlns="http://www.w3.org/1999/xhtml">text that has been rendered in a non-text form (e.g., an image) in order to achieve
a particular visual effect
</p>
<div xmlns="http://www.w3.org/1999/xhtml" class="note">
<p class="note-title marker">Note</p>
<p>This does not include <a href="#dfn-text">text</a> that is part of a picture that contains significant other visual content.
</p>
</div>
<aside xmlns="http://www.w3.org/1999/xhtml" class="example">
<p>A person's name on a nametag in a photograph.</p>
</aside>
</definition>
</dd>
<dt id="dfn-live">live</dt>
<dd>
<definition xmlns="">
<p xmlns="http://www.w3.org/1999/xhtml">information captured from a real-world event and transmitted to the receiver with
no more than a broadcast delay
</p>
<div xmlns="http://www.w3.org/1999/xhtml" class="note">
<p class="note-title marker">Note</p>
<p>A broadcast delay is a short (usually automated) delay, for example used in order
to give the broadcaster time to cue or censor the audio (or video) feed, but not sufficient
to allow significant editing.
</p>
</div>
<div xmlns="http://www.w3.org/1999/xhtml" class="note">
<p class="note-title marker">Note</p>
<p>If information is completely computer generated, it is not live.</p>
</div>
</definition>
</dd>
<dt id="dfn-media-alternative-for-text">media alternative for text</dt>
<dd>
<definition xmlns="">
<p xmlns="http://www.w3.org/1999/xhtml">media that presents no more information than is already presented in text (directly
or via text alternatives)
</p>
<div xmlns="http://www.w3.org/1999/xhtml" class="note">
<p class="note-title marker">Note</p>
<p>A media alternative for text is provided for those who benefit from alternate representations
of text. Media alternatives for text may be audio-only, video-only (including sign-language
video), or audio-video.
</p>
</div>
</definition>
</dd>
<dt id="dfn-non-text-content">non-text content</dt>
<dd>
<definition xmlns="">
<p xmlns="http://www.w3.org/1999/xhtml">any content that is not a sequence of characters that can be <a href="#dfn-programmatically-determined">programmatically determined</a> or where the sequence is not expressing something in <a href="#dfn-human-language">human language</a>
</p>
<div xmlns="http://www.w3.org/1999/xhtml" class="note">
<p class="note-title marker">Note</p>
<p>This includes <a href="#dfn-ascii-art">ASCII Art</a> (which is a pattern of characters), emoticons, leetspeak (which uses character substitution),
and images representing text
</p>
</div>
</definition>
</dd>
<dt id="dfn-prerecorded">prerecorded</dt>
<dd>
<definition xmlns="">
<p xmlns="http://www.w3.org/1999/xhtml">information that is not <a href="#dfn-live">live</a>
</p>
</definition>
</dd>
<dt id="dfn-programmatically-determined">programmatically determined</dt>
<dd>
<definition xmlns="">
<p xmlns="http://www.w3.org/1999/xhtml">determined by software from author-supplied data provided in a way that different
<a href="#dfn-user-agent">user agents</a>, including <a href="#dfn-assistive-technology">assistive technologies</a>, can extract and present this information to users in different modalities
</p>
<aside xmlns="http://www.w3.org/1999/xhtml" class="example">
<p>Determined in a markup language from elements and attributes that are accessed directly
by commonly available assistive technology.
</p>
</aside>
<aside xmlns="http://www.w3.org/1999/xhtml" class="example">
<p>Determined from technology-specific data structures in a non-markup language and exposed
to assistive technology via an accessibility API that is supported by commonly available
assistive technology.
</p>
</aside>
</definition>
</dd>
<dt id="dfn-sign-language">sign language</dt>
<dd>
<definition xmlns="">
<p xmlns="http://www.w3.org/1999/xhtml">a language using combinations of movements of the hands and arms, facial expressions,
or body positions to convey meaning
</p>
</definition>
</dd>
<dt id="dfn-synchronized-media">synchronized media</dt>
<dd>
<definition xmlns="">
<p xmlns="http://www.w3.org/1999/xhtml">
<a href="#dfn-audio">audio</a> or <a href="#dfn-video">video</a> synchronized with another format for presenting information and/or with time-based
interactive components, unless the media is a <a href="#dfn-media-alternative-for-text">media alternative for text</a> that is clearly labeled as such
</p>
</definition>
</dd>
<dt id="dfn-text">text</dt>
<dd>
<definition xmlns="">
<p xmlns="http://www.w3.org/1999/xhtml">sequence of characters that can be <a href="#dfn-programmatically-determined">programmatically determined</a>, where the sequence is expressing something in <a href="#dfn-human-language">human language</a>
</p>
</definition>
</dd>
<dt id="dfn-text-alternative">text alternative</dt>
<dd>
<definition xmlns="">
<p xmlns="http://www.w3.org/1999/xhtml">
<a href="#dfn-text">Text</a> that is programmatically associated with <a href="#dfn-non-text-content">non-text content</a> or referred to from text that is programmatically associated with non-text content.
Programmatically associated text is text whose location can be programmatically determined
from the non-text content.
</p>
<aside xmlns="http://www.w3.org/1999/xhtml" class="example">
<p>An image of a chart is described in text in the paragraph after the chart. The short
text alternative for the chart indicates that a description follows.
</p>
</aside>
<div xmlns="http://www.w3.org/1999/xhtml" class="note">
<p class="note-title marker">Note</p>
<p>Refer to <a href="https://www.w3.org/WAI/WCAG21/Understanding/conformance#text-alternatives">Understanding Text Alternatives</a> for more information.
</p>
</div>
</definition>
</dd>
<dt id="dfn-user-agent">user agent</dt>
<dd>
<definition xmlns="">
<p xmlns="http://www.w3.org/1999/xhtml">any software that retrieves and presents Web content for users</p>
<aside xmlns="http://www.w3.org/1999/xhtml" class="example">
<p>Web browsers, media players, plug-ins, and other programs — including <a href="#dfn-assistive-technology">assistive technologies</a> — that help in retrieving, rendering, and interacting with Web content.
</p>
</aside>
</definition>
</dd>
<dt id="dfn-video">video</dt>
<dd>
<definition xmlns="">
<p xmlns="http://www.w3.org/1999/xhtml">the technology of moving or sequenced pictures or images</p>
<div xmlns="http://www.w3.org/1999/xhtml" class="note">
<p class="note-title marker">Note</p>
<p>Video can be made up of animated or photographic images, or both.</p>
</div>
</definition>
</dd>
<dt id="dfn-video-only">video-only</dt>
<dd>
<definition xmlns="">
<p xmlns="http://www.w3.org/1999/xhtml">a time-based presentation that contains only <a href="#dfn-video">video</a> (no <a href="#dfn-audio">audio</a> and no interaction)
</p>
</definition>
</dd>
</details>
</section>
<section id="test-rules">
<h2>Test Rules</h2>
<p>The following are Test Rules for certain aspects of this Success Criterion. It is
not necessary to use these particular Test Rules to check for conformance with WCAG,
but they are defined and approved test methods. For information on using Test Rules,
see <a href="understanding-act-rules.html">Understanding Test Rules for WCAG Success Criteria</a>.
</p>
<ul>
<li><a href="/WAI/standards-guidelines/act/rules/1a02b0/proposed/">Audio and visuals of video element have transcript</a></li>
<li><a href="/WAI/standards-guidelines/act/rules/c5a4ea/proposed/">Video element visual content has accessible alternative</a></li>
</ul>
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