Understanding Guideline 1.1: Provide text alternatives for all non-text content
Intent of Guideline 1.1
The purpose of this guideline is to ensure that all non-text content is also available in text form. "Text form" refers to electronic text, not an image of text. Electronic text has the unique advantage that it can be rendered visually, auditorily, tactilely, or by any combination. As a result, information rendered in electronic text can be presented in whatever form best meets the needs of the user. It can also be easily enlarged, spoken in a voice that is easy to understand or rendered in whatever tactile form best meets the needs of a user.
Advisory Techniques for Guideline 1.1
Specific techniques for meeting each success criterion for this guideline are listed in the How to Meet sections for each success criterion (listed below). There are some techniques, however, for addressing this guideline that do not fall under any of the success criteria. These techniques are listed here. They are not required or sufficient for meeting any success criteria but these advisory techniques can make certain types of Web content more accessible to more people.
- All advisory techniques for this guideline relate to specific success criteria and are listed below.
How to Meet Success Criterion 1.1.1
Key Terms
- non-text content
-
content that is not represented by a Unicode character or sequence of Unicode characters when rendered in a user agent according to the formal specification of the content type
Note: This includes ASCII Art, which is a pattern of characters.
- text alternative
-
programmatically determined text that is used in place of non-text content, or text that is used in addition to non-text content and referred to from the programmatically determined text
- multimedia
-
audio or video synchronized with another type of media and/or with time-based interactive components
- live audio-only
-
A time-based live presentation that contains only audio (no video and no interaction).
- live video-only
-
A time-based live presentation that contains only video (no audio and no interaction).
- test or exercise that must use a particular sense
-
test where the content must be presented in a particular sensory format
Example: Color blindness test, hearing test, vision exercise, spelling test.
- specific sensory experience
-
a sensory experience that is not purely decorative and does not primarily convey important information or perform a function
- label
-
text, image, or sound that is presented to a user to identify a component within Web content
- pure decoration
-
serving only an aesthetic purpose, providing no information, and having no functionality.
- Assistive technology (in the context of this document)
-
a user agent that:
-
relies on services (such as retrieving Web content and parsing markup) provided by one or more other "host" user agents. Assistive technologies communicate data and messages with host user agents by using and monitoring APIs.
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provides services beyond those offered by the host user agents to meet the requirements of users with disabilities. Additional services include alternative renderings (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).
Example: Examples of assistive technologies that are important in the context of this document include the following:
-
screen magnifiers, which are used by people with visual disabilities to enlarge and change colors on the screen to improve the visual readability of rendered text and images;
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screen readers, which are used by people who are blind or have reading disabilities to read textual information through synthesized speech or braille displays;
-
voice recognition software, which may be used by people who have some physical disabilities;
-
alternative keyboards, which are used by people with certain physical disabilities to simulate the keyboard;
-
alternative pointing devices, which are used by people with certain physical disabilities to simulate mouse pointing and button activations.
Intent of this success criterion
The intent of this success criterion is to make information conveyed by non-text content accessible through the use of a text alternative. Text alternatives are a primary way for making information accessible because they can be rendered through any sensory modality (for example, visual, auditory or tactile) to match the needs of the user. Providing text alternatives allows the information to be rendered in a variety of ways by a variety of user agents. For example, a person who cannot see a picture can have the text alternative read aloud using synthesized speech. A person who cannot hear an audio file can have the text alternative displayed so that he or she can read it. In the future, text alternatives will also allow information to be more easily translated into sign language or into a simpler form of the same language.
Additional information
Non-text content can take a number of forms, and this success criterion specifies how each is to be handled.
For non-text content that presents information,
such as charts, diagrams, audio recordings, pictures, and animations, text alternatives can make the same information available in a form that can be rendered through any modality (for example, visual, auditory or tactile). Short and long text alternatives can be used as needed to convey the information in the non-text content. Note that
pre-recorded
audio-only and
pre-recorded
video-only files are covered here.
Live
-audio-only and
Live
-video-only files are covered below (see 3rd paragraph following this one).
For non-text content that responds to user input
, such as images used as submit buttons or complex animations, text alternatives are provided if at all possible. If it is not possible to make the function available in any form of text (including with the use of links, etc.), then the purpose of the non-text content is identified in text so that the person at least knows what the non-text content is and why it is there.
Non-text content that is multimedia
is made accessible through guideline 1.2. However it is important that users know what it is when they encounter it on a page so they can decide what action if any they want to take with it. A text alternative that describes the multimedia and/or gives its title is therefore provided.
Live Audio-only and live video-only files
- It is much more difficult to provide text alternatives that convey the same information as live audio-only and live video-only content. For these types of non-text content, text alternatives provide a descriptive label.
Sometimes a test or exercise must use a particular sense. Audio or visual information is provided that cannot be changed to text because the test or exercise must be conducted using that sense. For example, a hearing test would be invalid if a text alternative were provided. A visual skill development exercise would similarly make no sense in text form. And a spelling test with text alternatives would not be very effective. For these cases, text alternatives should be provided to describe the purpose of the non-text content; of course, the text alternatives would not provide the same information needed to pass the test.
Sometimes content is primarily intended to create a specific sensory experience that words cannot fully capture. Examples include a symphony performance, works of visual art etc. For such content, text alternatives at least identify the non-text content with a descriptive label. Providing what description is possible is also desired. If the intent of the author in creating the content - or the intent of the page author in putting the content on the page - is known and can be described, this is also very useful.
Finally, there is non-text content that really is not meant to be seen or understood by the user. Transparent images used to move text over on a page; a one pixel transparent "web-bug" that tells the author when the page is viewed; and a swirl in the corner that conveys no information but just fills up a blank space to create an aesthetic effect are all examples of this. Putting alternative text on such items just distracts people using screen readers from the content on the page. Not marking the content in any way, though, leaves users guessing what the non-text content is and what information they may have missed (even though they have not missed anything in reality). This type of non-text content, therefore, is marked or implemented in a way that assistive technologies (AT) will ignore it and not present anything to the user.
Techniques for Addressing Success Criterion 1.1.1
Each numbered item in this section represents a technique or combinations of techniques that the WCAG Working Group deems to be sufficient to meet success criterion 1.1.1 as long as the technologies used are in the baseline you are using. All techniques listed would be helpful to some users. However, they only satisfy the success criterion if all of the technologies used are in your baseline. (Use of technologies not in the baseline is allowed, but an alternate conformant version would be required per success criterion 4.2.1.)
Instructions: 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.
Situation E: If the non-text content should be ignored by assistive technology
-
Implementing or Marking the non-text content so that it will be ignored by AT USING one of the technology-specific techniques listed below
Technology-Specific Techniques
Providing short text alternatives in HTML
Providing long descriptions in HTML
Allowing AT to Ignore Non-text Content using HTML
Allowing AT to Ignore Non-text Content using CSS
Common Failures Identified by the Working Group
The following are common mistakes that are considered failures of success criterion 1.1.1 by the WCAG Working Group.
Additional Techniques (Advisory) for 1.1.1
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.
(none currently documented)
General Techniques for Informative Non-Text Content(Advisory)
-
Identifying informative non-text content (future link).
-
Keeping short descriptions short (future link).
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Describing images that include text (future link).
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Providing a longer description of the non-text content where only a descriptive label is required using a technology-specific technique (for a technology in your baseline) for long description listed above. (future link)
General Techniques for Live Non-Text Content (Advisory)
-
Linking to live textual information, e.g., if it is a traffic web cam, linking to a site that provides textual traffic reports (future link)
-
Providing a transcript of a live audio only presentation after the fact (future link)
HTML Techniques (Advisory)
-
Writing for browsers that do not support frame (future link)
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Providing alternative content for iframe (future link)
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Providing text and non-text alternatives for object (future link)
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Not using long descriptions for iframe (future link)
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Providing redundant text links for client-side image maps (future link)
CSS Techniques (Advisory)
-
Using CSS margin and padding rules instead of spacer images (future link)
-
Using CSS background, :before or :after rules for decorative images instead of img elements (future link)
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Displaying empty table cells (future link)
Benefits: How Success Criterion 1.1.1 helps people with disabilities
-
People who are blind, have low vision, or have cognitive limitations can have text alternatives read aloud to them by assistive technology.
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People who have trouble reading text may use tools that both read text aloud and highlight the words as they are read. In some cases, it may be difficult for someone to recognize visual information and the text alternative may help him or her understand the purpose of the non-text content.
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People who are deaf, are hard of hearing, or who are having trouble understanding audio information for any reason can read the text presentation or (in the future) have it translated and presented as sign language by assistive technology.
-
People who are deaf-blind can read the text in braille.
-
Additionally, text alternatives support the ability to search for non-text content and to repurpose content in a variety of ways.
Examples of Success Criterion 1.1.1
-
A data chart
A bar chart compares how many widgets were sold in June, July, and August. The short label says, "Figure one - Sales in June, July and August." The longer description identifies the type of chart, provides a high-level summary of the data comparable to that available from the chart, and provides the data in a table.
-
An audio recording of a speech (no video)
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.
-
An animation that illustrates how a car engine works
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. All that is needed is a description of the image. From "How car engines work: Internal combustion"
-
A traffic Web camera
A Web site allows users to select from a variety of Web cameras positioned throughout a major city. After a camera is selected, the image updates every two minutes. A short text alternative identifies the Web camera as "traffic Web camera." The site also provides a table of travel times for each of the routes covered by the Web cameras. The table is also updated every two minutes.
-
A photograph of an historic event in a news story
A photograph of two world leaders shaking hands accompanies a news story about an international summit meeting. The text alternative says, "President X of Country X shakes hands with Prime Minister Y of country Y."
-
A photograph of a historic event in content discussing diplomatic relationships
The same image is used in a different context intended to explain nuances in diplomatic encounters. The image of the president shaking hands with the prime minister appears on a Web site discussing intricate diplomatic relationships. The first text alternative reads, "President X of country X shakes hands with Prime Minister Y of country Y on January 2, 2009." An additional text alternative describes the room where the leaders are standing as well as the expressions on the leaders' faces, and identifies the other people in the room. The additional description might be included on the same page as the photograph or in a separate file associated with the image through a link or other standard programmatic mechanism.
-
An audio recording
The Web page described in the previous example includes a link to an audio recording of the leaders' press conference. 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.
Understanding Guideline 1.2: Provide synchronized alternatives for multimedia
Intent of Guideline 1.2
The purpose of this guideline is to provide access to multimedia. Multimedia is defined in the glossary as:
multimedia: audio or video synchronized with another type of media and/or with time-based interactive components
Note that an audio file accompanied by interaction is covered here, as is a video-only file that involves interaction. These are covered because interaction must take place at a particular time. Having a text transcript that said, "for more information, click now," would not be very helpful since the reader would have no idea when the audio said, "now." As a result, synchronized captions would be needed.
Sometimes, there is so much dialogueue that audio descriptions cannot fit into existing pauses in the dialogueue. The option at Level 1 to provide a full multimedia text alternative including any interaction instead of audio descriptions for multimedia would allow access to all of the information in the multimedia. This option also allows access to the visual information in non-visual form when audio description is not provided for some other reason.
For multimedia that includes interaction, interactive elements (for example links) could be embedded in the full multimedia text alternative.
This guideline also includes (at Level 3) sign language interpretation for multimedia as well as an approach called extended audio descriptions. In extended audio description, the video is frozen periodically to allow more audio description to take place than is possible in the existing pauses in the dialogueue.
Advisory Techniques for Guideline 1.2
Specific techniques for meeting each success criterion for this guideline are listed in the How to Meet sections for each success criterion (listed below). There are some techniques, however, for addressing this guideline that do not fall under any of the success criteria. These techniques are listed here. They are not required or sufficient for meeting any success criteria but these advisory techniques can make certain types of Web content more accessible to more people.
- All advisory techniques for this guideline relate to specific success criteria and are listed below.
How to Meet Success Criterion 1.2.1
- captions
-
text presented and synchronized with multimedia to provide not only the speech, but also sound effects and sometimes speaker identification
Note: In some countries, the term "subtitle" is used to refer to dialogue only and "captions" is used as the term for dialogue plus sounds and speaker identification. In other countries, subtitle (or its translation) is used to refer to both.
- multimedia
-
audio or video synchronized with another type of media and/or with time-based interactive components
The intent of this success criterion is to enable people who are deaf or hard of hearing to watch multimedia presentations. Captions provide the part of the content available via the audio track. Captions not only include dialogue, but identify who is speaking and note important sounds.
Each numbered item in this section represents a technique or combinations of techniques that the WCAG Working Group deems to be sufficient to meet success criterion 1.2.1 as long as the technologies used are in the baseline you are using. All techniques listed would be helpful to some users. However, they only satisfy the success criterion if all of the technologies used are in your baseline. (Use of technologies not in the baseline is allowed, but an alternate conformant version would be required per success criterion 4.2.1.)
The following are common mistakes that are considered failures of success criterion 1.2.1 by the WCAG Working Group.
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.
(none currently documented)
Additional Technology-Independent Techniques (Advisory)
Additional SMIL 1.0 Techniques (Advisory)
Additional SMIL 2.0 Techniques (Advisory)
People who are deaf or have a hearing loss can access the auditory information in the multimedia content through captions.
-
A captioned tutorial
A video clip shows how to tie a knot. The captions read,
"(music)
Using rope to tie knots was an important skill
for the likes of sailors, soldiers and woodsmen.."
From Sample Transcript Formatting by Whit Anderson.
(none currently documented)
Other Captioning Resources
How to Meet Success Criterion 1.2.2
- audio description
-
narration added to the soundtrack to describe important visual details that cannot be understood from the main soundtrack alone
Note 1:
Audio descriptions of video provide information about actions, characters, scene changes, and on-screen text.
Note 2:
In standard audio description, narration is added during existing pauses in dialogue. (See also Extended audio descriptions.)
- full multimedia text alternative including any interaction
-
document including correctly sequenced descriptions of all visual settings, actions, and non-speech sounds combined with descriptive transcripts of all dialogue and a means of achieving any outcomes that are achieved using interaction during the multimedia
Note: A screenplay used to create the multimedia content would meet this definition only if it was corrected to accurately represent the final multimedia after editing.
- multimedia
-
audio or video synchronized with another type of media and/or with time-based interactive components
The intent of this success criterion is to provide people who are blind or visually impaired access to the visual information in a multimedia presentation. This success criterion describes two approaches, either of which can be used.
One approach is to provide Audio Description of the video content. The audio description augments the audio portion of the presentation with the information needed when the video portion is not available. During existing pauses in dialogueue, audio descriptions provide information about actions, characters, scene changes, and on-screen text that are important and are not described or spoken in the main sound track.
The second approach involves providing all of the information in the multimedia (both visual and auditory) in text form. A full multimedia text alternative including any interaction provides a running description of all that is going on in the multimedia content. The full multimedia text alternative reads something like a screenplay or book. Unlike audio descriptions, the descriptions of the video portion are not constrained to just the pauses in the existing dialogueue. 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 dialogueue are included. The sequence of descriptions and dialogueue transcripts is the same as the sequence in the multimedia itself. As a result, the full multimedia text alternative can provide a much more complete representation of the multimedia content than audio description alone.
If there is any interaction as part of the multimedia presentation (e.g. "press now to answer the question") then the full multimedia text alternative would provide hyperlinks or whatever is needed to provide parallel functionality.
Each numbered item in this section represents a technique or combinations of techniques that the WCAG Working Group deems to be sufficient to meet success criterion 1.2.2 as long as the technologies used are in the baseline you are using. All techniques listed would be helpful to some users. However, they only satisfy the success criterion if all of the technologies used are in your baseline. (Use of technologies not in the baseline is allowed, but an alternate conformant version would be required per success criterion 4.2.1.)
-
Providing a sound track that includes audio description as the primary sound track
-
Providing a sound track that includes audio description
AND associating it with the multimedia content using a technology-specific technique (for a technology in your baseline)
-
Providing audio description in its own sound track (future link) AND merging the description track with the original soundtrack of the multimedia content at runtime using a technology-specific technique (for a technology in your baseline)
-
Providing a full multimedia text alternative including any interaction
The following are common mistakes that are considered failures of success criterion 1.2.2 by the WCAG Working Group.
(No failures currently documented)
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.
-
A movie with audio description.
Describer: A title, "Teaching Evolution Case Studies. Bonnie Chen." A teacher shows photographs of birds with long, thin beaks.
Bonnie Chen: "These photos were all taken at the Everglades."
Describer: The teacher hands each student two flat, thin wooden sticks.
Bonnie Chen: "Today you will pretend to be a species of wading bird that has a beak like this."
Describer: The teacher holds two of the sticks to her mouth making the shape of a beak.
Transcript of audio based on the first few minutes of "Teaching Evolution Case Studies, Bonnie Chen" (copyright WGBH and Clear Blue Sky Productions, Inc.)
-
Full multimedia text alternative for a training video
A company purchases a Training video for use by its employees and puts it on the companies intranet. The video involves explaining use of a new technology and has a person talking and showing things at the same time. Since there is no place to insert audio description of the visual demonstrations during gaps in dialogueue, the company provides a full multimedia text alternative that all employees, including those who cannot see the demonstrations, can use to better understand what is being presented.
How to Meet Success Criterion 1.2.3
- audio description
-
narration added to the soundtrack to describe important visual details that cannot be understood from the main soundtrack alone
Note 1:
Audio descriptions of video provide information about actions, characters, scene changes, and on-screen text.
Note 2:
In standard audio description, narration is added during existing pauses in dialogue. (See also Extended audio descriptions.)
- multimedia
-
audio or video synchronized with another type of media and/or with time-based interactive components
The intent of this success criterion is to provide people who are blind or visually impaired access to the visual information in a multimedia presentation. The audio description augments the audio portion of the presentation with the information needed when the video portion is not available. During existing pauses in dialogueue, audio descriptions provide information about actions, characters, scene changes, and on-screen text that are important and are not described or spoken in the main sound track.
Each numbered item in this section represents a technique or combinations of techniques that the WCAG Working Group deems to be sufficient to meet success criterion 1.2.3 as long as the technologies used are in the baseline you are using. All techniques listed would be helpful to some users. However, they only satisfy the success criterion if all of the technologies used are in your baseline. (Use of technologies not in the baseline is allowed, but an alternate conformant version would be required per success criterion 4.2.1.)
The following are common mistakes that are considered failures of success criterion 1.2.3 by the WCAG Working Group.
(No failures currently documented)
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.
-
A movie with audio description.
Describer: A title, "Teaching Evolution Case Studies. Bonnie Chen." A teacher shows photographs of birds with long, thin beaks.
Bonnie Chen: "These photos were all taken at the Everglades."
Describer: The teacher hands each student two flat, thin wooden sticks.
Bonnie Chen: "Today you will pretend to be a species of wading bird that has a beak like this."
Describer: The teacher holds two of the sticks to her mouth making the shape of a beak.
Transcript of audio based on the first few minutes of "Teaching Evolution Case Studies, Bonnie Chen" (copyright WGBH and Clear Blue Sky Productions, Inc.)
How to Meet Success Criterion 1.2.4
- captions
-
text presented and synchronized with multimedia to provide not only the speech, but also sound effects and sometimes speaker identification
Note: In some countries, the term "subtitle" is used to refer to dialogue only and "captions" is used as the term for dialogue plus sounds and speaker identification. In other countries, subtitle (or its translation) is used to refer to both.
- multimedia
-
audio or video synchronized with another type of media and/or with time-based interactive components
The intent of this success criterion is to enable people who are deaf or hard of hearing to watch
real-time
presentations. Captions provide the part of the content available via the audio track. Captions not only include dialogue, but also identify who is speaking and notate sound effects and other significant audio.
Each numbered item in this section represents a technique or combinations of techniques that the WCAG Working Group deems to be sufficient to meet success criterion 1.2.4 as long as the technologies used are in the baseline you are using. All techniques listed would be helpful to some users. However, they only satisfy the success criterion if all of the technologies used are in your baseline. (Use of technologies not in the baseline is allowed, but an alternate conformant version would be required per success criterion 4.2.1.)
The following are common mistakes that are considered failures of success criterion 1.2.4 by the WCAG Working Group.
(No failures currently documented)
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.
(none currently documented)
How to Meet Success Criterion 1.2.5
- sign language interpretation
-
translation of spoken words and other audible information into a language that uses a simultaneous combination of handshapes, facial expressions, and orientation and movement of the hands, arms, or body to convey meaning
Note: Although some languages have a signed counterpart, most sign languages are independent languages that are unrelated to the spoken language of the same country or culture.
- multimedia
-
audio or video synchronized with another type of media and/or with time-based interactive components
The intent of this success criterion is to enable people who are deaf or hard of hearing and who are fluent in the sign language to watch multimedia presentations. Many people find it easier to follow sign language than to read the text of captions, since the captions are often a second language to them.
Each numbered item in this section represents a technique or combinations of techniques that the WCAG Working Group deems to be sufficient to meet success criterion 1.2.5 as long as the technologies used are in the baseline you are using. All techniques listed would be helpful to some users. However, they only satisfy the success criterion if all of the technologies used are in your baseline. (Use of technologies not in the baseline is allowed, but an alternate conformant version would be required per success criterion 4.2.1.)
The following are common mistakes that are considered failures of success criterion 1.2.5 by the WCAG Working Group.
(No failures currently documented)
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.
(none currently documented)
-
People whose primary language is a sign language sometimes have limited reading ability. These individuals may not be able to read and comprehend the captions and thus require a sign language interpretation to gain access to the multimedia content.
-
Some people who communicate using sign language and are proficient readers may have impaired vision which may make it difficult to read the captions on the screen. A sign language interpretation may be easier to view.
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Example 1. A corporation is making an important announcement to all of its employees. The meeting will be held in the main headquarters and streamed to the Web. A sign language interpreter is provided at the meeting location. The live video includes a full view of the sign language interpreter as well as the person presenting.
-
Example 2. The same announcement described in example 1 is also Webcast to remote employees. Since there is only one display available for this, the sign language interpreter is shown in the corner of the display.
-
Example 3. A university is providing an on-line version of a particular lecture by creating a multimedia presentation of the professor delivering the lecture. The presentation includes video of the professor speaking and demonstrating a science experiment. A sign language interpretation of the lecture is created and presented on the Web with the multimedia version.
How to Meet Success Criterion 1.2.6
- extended audio descriptions
-
audio descriptions that are added to an audiovisual presentation by pausing the video so that there is time to add additional description
Note: This technique is only used when the sense of the video would be lost without the additional audio description.
- multimedia
-
audio or video synchronized with another type of media and/or with time-based interactive components
The intent of this success criterion is to provide people who are blind or visually impaired access to a multimedia presentation beyond that which can be provided by standard audio descriptions. This is done by periodically freezing the multimedia presentation and playing additional audio description. The multimedia presentation is then resumed.
Because it disrupts viewing for those who do not need the additional description, techniques that allow you to turn the feature on and off are often provided. Alternately, versions with and without the additional description can be provided.
Each numbered item in this section represents a technique or combinations of techniques that the WCAG Working Group deems to be sufficient to meet success criterion 1.2.6 as long as the technologies used are in the baseline you are using. All techniques listed would be helpful to some users. However, they only satisfy the success criterion if all of the technologies used are in your baseline. (Use of technologies not in the baseline is allowed, but an alternate conformant version would be required per success criterion 4.2.1.)
The following are common mistakes that are considered failures of success criterion 1.2.6 by the WCAG Working Group.
(No failures currently documented)
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.
(none currently documented)
Additional SMIL 1.0 Techniques
Additional SMIL 2.0 Techniques
-
People who are blind, people with low vision who cannot see the screen, as well as those with cognitive limitations who have difficulty interpreting visually what is happening, often use audio descriptions of the visual information. However, if there is too much dialogue the audio descriptions are insufficient. Extended audio descriptions can provide the additional information they needed to understand the video.
-
Example 1. Video of a lecture. A physics professor is giving a lecture. He makes freehand sketches on the whiteboard, speaking rapidly as he draws. As soon as he has finished discussing one problem, he erases the drawing and makes another sketch while continuing to speak and gesture with his other hand. The video is paused between problems, and extended audio descriptions of the professor’s drawings and gestures are provided; the video is then resumed.
How to Meet Success Criterion 1.2.7
Key Terms
- full multimedia text alternative including any interaction
-
document including correctly sequenced descriptions of all visual settings, actions, and non-speech sounds combined with descriptive transcripts of all dialogue and a means of achieving any outcomes that are achieved using interaction during the multimedia
Note: A screenplay used to create the multimedia content would meet this definition only if it was corrected to accurately represent the final multimedia after editing.
Intent of this success criterion
The intent of this success criterion is to make audio visual material available to individuals whose vision is too poor to reliably read captions and whose hearing is too poor to reliably hear dialogue and audio descriptions. This is done by providing a full multimedia text alternative including any interaction.
This approach involves providing all of the information in the multimedia (both visual and auditory) in text form. A full multimedia text alternative including any interaction provides a running description of all that is going on in the multimedia content. The full multimedia text alternative reads something like a book. Unlike audio descriptions, the descriptions of the video portion are 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 multimedia itself. As a result, the full multimedia text alternative can provide a much more complete representation of the multimedia content than audio description alone.
If there is any interaction as part of the multimedia presentation (e.g. "press now to answer the question") then the full multimedia text alternative would provide hyperlinks or whatever is needed to provide parallel functionality.
Individuals whose vision is too poor to reliably read captions and whose hearing is too poor to reliably hear dialogue can access the full multimedia text alternative by using a refreshable braille display.
Techniques for Addressing Success Criterion 1.2.7
Each numbered item in this section represents a technique or combinations of techniques that the WCAG Working Group deems to be sufficient to meet success criterion 1.2.7 as long as the technologies used are in the baseline you are using. All techniques listed would be helpful to some users. However, they only satisfy the success criterion if all of the technologies used are in your baseline. (Use of technologies not in the baseline is allowed, but an alternate conformant version would be required per success criterion 4.2.1.)
Technology-Specific Techniques
Linking to a full multimedia text alternative including any interaction in HTML
Common Failures Identified by the Working Group
The following are common mistakes that are considered failures of success criterion 1.2.7 by the WCAG Working Group.
(No failures currently documented)
Additional Techniques (Advisory) for 1.2.7
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.
(none currently documented)
General Techniques (Advisory)
Benefits: How Success Criterion 1.2.7 helps people with disabilities
Examples of Success Criterion 1.2.7
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Example 1. Full multimedia text alternative for a training video
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 a full multimedia text alternative that all clients, including those who can neither see the demonstrations nor hear the explanations in the multimedia, can use to better understand what is being presented.
Related resources
(none currently documented)
Understanding Guideline 1.3: Ensure that information and structure can be separated from presentation
Intent of Guideline 1.3
The purpose of this guideline is to ensure that all information is available in a form that can be perceived by all users. If all of the information is available in a form that can be determined by software, then it can be presented to users in different ways (visually, audibly, tactilely etc.). If information is embedded in a particular presentation in such a way that the information cannot be separated from the presentation, then it cannot be rendered in other formats as needed by the user.
The success criteria under this guideline all seek to ensure that different types of information that are often encoded in presentation are also available so that they can be presented in other modalities.
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structure: the way the parts of an authored unit are organized in relation to each other; and the way a collection of Web units is organized
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presentation: rendering of the content and structure in a form that can be perceived by the user
Advisory Techniques for Guideline 1.3
Specific techniques for meeting each success criterion for this guideline are listed in the How to Meet sections for each success criterion (listed below). There are some techniques, however, for addressing this guideline that do not fall under any of the success criteria. These techniques are listed here. They are not required or sufficient for meeting any success criteria but these advisory techniques can make certain types of Web content more accessible to more people.
How to Meet Success Criterion 1.3.1
Key Terms
- presentation
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rendering of the content and structure in a form that can be perceived by the user
- programmatically determined
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determined by software from data provided in a user-agent-supported manner such that the user agents can extract and present this information to users in different modalities
- user agent
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any software that retrieves and renders Web content for users
Example: Web browsers, media players, plug-ins, and other programs — including assistive technologies — that help in retrieving and rendering Web content.
- Assistive technology (in the context of this document)
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a user agent that:
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relies on services (such as retrieving Web content and parsing markup) provided by one or more other "host" user agents. Assistive technologies communicate data and messages with host user agents by using and monitoring APIs.
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provides services beyond those offered by the host user agents to meet the requirements of users with disabilities. Additional services include alternative renderings (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).
Example: Examples of assistive technologies that are important in the context of this document include the following:
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screen magnifiers, which are used by people with visual disabilities to enlarge and change colors on the screen to improve the visual readability of rendered text and images;
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screen readers, which are used by people who are blind or have reading disabilities to read textual information through synthesized speech or braille displays;
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voice recognition software, which may be used by people who have some physical disabilities;
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alternative keyboards, which are used by people with certain physical disabilities to simulate the keyboard;
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alternative pointing devices, which are used by people with certain physical disabilities to simulate mouse pointing and button activations.
Intent of this success criterion
The intent of this success criterion is to ensure that information and relationships that are implied by visual or auditory formatting are preserved when the presentation format changes. For example, the presentation format changes when the content is read by a screen reader or when a user style sheet is substituted for the style sheet provided by the author.
Sighted users perceive structure through various visual cues — headings are often in a larger, bold font separated from paragraphs by blank lines; list items are preceded by a bullet and perhaps indented; paragraphs are separated by a blank line; items that share a common characteristic are organized into tabular rows and columns; form fields may be positioned as groups that share text labels; a different background color may be used to indicate that several items are related to each other; and so on.
Auditory cues may be used as well. For example, a chime might indicate the beginning of a new section; a change in voice pitch or speech rate may be used to emphasize important information or to indicate quoted text; etc.
The purpose of this success criterion is to ensure that when such relationships are perceivable to one set of users, those relationships can be made to be perceivable to all.
Techniques for Addressing Success Criterion 1.3.1
Each numbered item in this section represents a technique or combinations of techniques that the WCAG Working Group deems to be sufficient to meet success criterion 1.3.1 as long as the technologies used are in the baseline you are using. All techniques listed would be helpful to some users. However, they only satisfy the success criterion if all of the technologies used are in your baseline. (Use of technologies not in the baseline is allowed, but an alternate conformant version would be required per success criterion 4.2.1.)
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Making information and relationships conveyed through presentation programmatically determinable USING the technology-specific techniques below (for a technology in your baseline)
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Using semantic elements to mark up structure
Technology-Specific Techniques
Client-Side Scripting Techniques
Common Failures Identified by the Working Group
The following are common mistakes that are considered failures of success criterion 1.3.1 by the WCAG Working Group.