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<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en">
<head>
<meta charset="UTF-8" />
<title>Understanding Success Criterion 1.2.1: Audio-only and Video-only (Prerecorded)</title>
<link rel="stylesheet" type="text/css" href="https://www.w3.org/StyleSheets/TR/2016/base" />
<link rel="stylesheet" type="text/css" href="base.css" />
<link rel="stylesheet" type="text/css" href="understanding.css" />
<link rel="stylesheet" type="text/css" href="slicenav.css" />
</head>
<body>
<nav>
<ul id="navigation">
<li><a href="." title="Table of Contents">Contents</a></li>
<li><a href="time-based-media"><abbr title="Guideline">GL</abbr>: Time-based Media</a></li>
<li><a href="non-text-content">Previous <abbr title="Success Criterion">SC</abbr>: Non-text Content</a></li>
<li><a href="captions-prerecorded">Next <abbr title="Success Criterion">SC</abbr>: Captions (Prerecorded)</a></li>
</ul>
</nav>
<nav class="navtoc">
<p>On this page:</p>
<ul id="navbar">
<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>
</ul>
</nav>
<h1>Understanding Success Criterion 1.2.1: Audio-only and Video-only (Prerecorded)</h1>
<blockquote class="scquote">
<p>Success Criterion <a href="https://www.w3.org/TR/WCAG21/#audio-only-and-video-only-prerecorded" style="font-weight: bold;">1.2.1 Audio-only and Video-only (Prerecorded)</a> (Level A): For <a href="#dfn-prerecorded">prerecorded</a>
<a href="#dfn-audio-only">audio-only</a> and prerecorded <a href="#dfn-video-only">video-only</a> media, the following are true, except when the audio or video is a <a href="#dfn-media-alternative-for-text">media alternative for text</a> and is clearly labeled as such:
</p>
<dl>
<dt>Prerecorded Audio-only</dt>
<dd>
<p>An <a href="#dfn-alternative-for-time-based-media">alternative for time-based media</a> is provided that presents equivalent information for prerecorded audio-only content.
</p>
</dd>
<dt>Prerecorded Video-only</dt>
<dd>
<p>Either an alternative for time-based media or an audio track is provided that presents
equivalent information for prerecorded video-only content.
</p>
</dd>
</dl>
</blockquote>
<main>
<section id="intent">
<h2>Intent</h2>
<p>The intent of this Success Criterion is to make information conveyed by prerecorded
audio-only and prerecorded video-only content available to all users. Alternatives
for time-based media that are text based make information accessible because text
can be rendered through any sensory modality (for example, visual, auditory or tactile)
to match the needs of the user. In the future, text could also be translated into
symbols, sign language or simpler forms of the language (future).
</p>
<p>An example of pre-recorded video with no audio information or user interaction is
a silent movie. The purpose of the transcript is to provide an equivalent to what
is presented visually. For prerecorded video content, authors have the option to provide
an audio track. The purpose of the audio alternative is to be an equivalent to the
video. This makes it possible for users with and without vision impairment to review
content simultaneously. The approach can also make it easier for those with cognitive,
language and learning disabilities to understand the content because it would provide
parallel presentation.
</p>
<div class="note">
<div role="heading" class="note-title marker" aria-level="3">Note</div>
<div>
<p>A text equivalent is not required for audio that is provided as an equivalent for
video with no audio information. For example, it is not required to caption video
description that is provided as an alternative to a silent movie.
</p>
</div>
</div>
<p>See also
<a href="audio-only-live">1.2.4: Audio-only (Live)</a>
</p>
</section>
<section id="benefits">
<h2>Benefits</h2>
<ul>
<li>This Success Criterion helps people who have difficulty perceiving visual content.
Assistive technology can read text alternatives aloud, present them visually, or convert
them to braille.
</li>
<li>Alternatives for timed-based media that are text based may help some people who have
difficulty understanding the meaning of prerecorded video content.
</li>
<li>People who are deaf, are hard of hearing, or who are having trouble understanding
audio information for any reason can read the text presentation. Research is ongoing
regarding automatic translation of text into sign language.
</li>
<li>People who are deaf-blind can read the text in braille.</li>
<li>Additionally, text supports the ability to search for non-text content and to repurpose
content in a variety of ways.
</li>
</ul>
</section>
<section id="examples">
<h2>Examples</h2>
<ul>
<li>
<p>
<strong>An audio recording of a speech</strong>
</p>
<p>The link to an audio clip says, "Chairman's speech to the assembly." A link to a text
transcript is provided immediately after the link to the audio clip.
</p>
</li>
<li>
<p>
<strong>An audio recording of a press conference</strong>
</p>
<p>A Web page includes a link to an audio recording of a press conference that identifies
the audio recording. The page also links to a text transcript of the press conference.
The transcript includes a verbatim record of everything the speakers say. It identifies
who is speaking as well as noting other significant sounds that are part of the recording,
such as applause, laughter, questions from the audience, and so on.
</p>
</li>
<li>
<p>
<strong>An animation that illustrates how a car engine works</strong>
</p>
<p>An animation shows how a car engine works. There is no audio and the animation is
part of a tutorial that describes how an engine works. Since the text of the tutorial
already provides a full explanation, the media is an alternative for text and the
text alternative includes only a brief description of the animation and refers to
the tutorial text for more information.
</p>
</li>
<li>
<p>
<strong>A video-only file with an audio track</strong>
</p>
<p>A silent movie includes an audio track which includes a description of the action
in the video.
</p>
</li>
</ul>
</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.rnib.org.uk/travel-downloads-podcasts-and-apps?List=be9c76d3-7ad0-4e03-a1a0-e6f6953b8178&ID=16">Overcoming the challenge of podcast transcription</a>
</li>
<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="audio-only-and-video-only-prerecorded-situation-0">
<h4>Situation A: If the content is prerecorded audio-only:</h4>
<ol>
<li>
<a class="general" href="https://www.w3.org/WAI/WCAG21/Techniques/general/G158">G158: Providing an alternative for time-based media for audio-only content</a>
</li>
</ol>
</section>
<section class="situation" id="audio-only-and-video-only-prerecorded-situation-1">
<h4>Situation B: If the content is prerecorded video-only:</h4>
<ol>
<li>
<a class="general" href="https://www.w3.org/WAI/WCAG21/Techniques/general/G159">G159: Providing an alternative for time-based media for video-only content</a>
</li>
<li>
<a class="general" href="https://www.w3.org/WAI/WCAG21/Techniques/general/G166">G166: Providing audio that describes the important video content and describing it as such</a>
</li>
</ol>
</section>
</section>
<section id="advisory">
<h3>Advisory Techniques</h3>
<p>Although not required for conformance, the following additional techniques should
be considered in order to make content more accessible. Not all techniques can be
used or would be effective in all situations.</p>
<ul>
<li>
<a class="html" href="https://www.w3.org/WAI/WCAG21/Techniques/html/H96">H96: Using the track element to provide audio descriptions</a>
</li>
</ul>
</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://www.w3.org/WAI/WCAG21/Techniques/failures/F30">F30: Failure of Success Criterion 1.1.1 and 1.2.1 due to using text alternatives that are
not alternatives (e.g., filenames or placeholder text)</a>
</li>
<li>
<a class="failure" href="https://www.w3.org/WAI/WCAG21/Techniques/failures/F67">F67: Failure of Success Criterion 1.1.1 and 1.2.1 due to providing long descriptions for
non-text content that does not serve the same purpose or does not present the same
information</a>
</li>
</ul>
</section>
</section>
<section id="key-terms">
<h2>Key Terms</h2>
<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">
<div role="heading" class="note-title marker" aria-level="2">Note</div>
<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-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">
<div role="heading" class="note-title marker" aria-level="2">Note</div>
<p>Audio can be created synthetically (including speech synthesis), recorded from real
world sounds, or both.
</p>
</div>
</definition>
</dd>
<dt id="dfn-audio-only">audio-only</dt>
<dd>
<definition xmlns="">
<p xmlns="http://www.w3.org/1999/xhtml">a time-based presentation that contains only <a href="#dfn-audio">audio</a> (no <a href="#dfn-video">video</a> and no interaction)
</p>
</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">
<div role="heading" class="note-title marker" aria-level="2">Note</div>
<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">
<div role="heading" class="note-title marker" aria-level="2">Note</div>
<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">
<div role="heading" class="note-title marker" aria-level="2">Note</div>
<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-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-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">
<div role="heading" class="note-title marker" aria-level="2">Note</div>
<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>
</section>
</main>
</body>
</html>