For all non-text content that is used to convey information, text alternatives identify the non-text content and convey the same information. For multimedia, provide a text-alternative that identifies the multimedia. Guide to 1.1 L1 SC1
Note: Refer to guideline 1.2 for requirements for synchronized alternatives for multimedia.
For functional non-text content, text alternatives serve the same purpose as the non-text content. If text alternatives can not serve the same purpose as the functional non-text content, text alternatives identify the purpose of the functional non-text content
Note: Non-text content that uses technologies outside the baseline must satisfy guideline 4.2.
For non-text content that is intended to create a specific sensory experience, text alternatives at least identify the non-text content with a descriptive label.
Non-text content that is not functional, is not used to convey information, and does not create a specific sensory experience is implemented such that it can be ignored by assistive technology.
For live audio-only or live video-only content, text alternatives at least identify the purpose of the content with a descriptive label.
Note: Refer to guideline 1.2 for guidance on content that combines live audio and video.
For prerecorded multimedia content, a combined transcript of captions and audio descriptions of video is available.
Guideline 1.1 (text-equiv) Issues
People who are blind, have low vision, have cognitive disabilities can have text alternatives read aloud to them by assistive technology.
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.
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 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.
Example 1: an image used as a button.
A magnifying glass icon is used to link to the search page of a Web site. A screen reader identifies the button as a link and speaks the text alternative, "Search."
Example 2: 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.
Example 3: 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.
Example 4: a recording of a symphony.
The Mars Philharmonic Orchestra's "Upcoming performances" page has a link to a 3 minute clip of the orchestra's rendition of Beethoven's 5th Symphony. The purpose is to encourage readers to buy tickets to a live performance. The link to the audio clip says, "Beethoven's 5th Symphony performed by the Mars Philharmonic Orchestra." On the same page is information about Beethoven and the 5th Symphony. Elsewhere on the Mars Philharmonic Orchestra's Web site is an educational area. There is a link to the same 3 minute clip of the orchestra performing Beethoven's 5th Symphony. The link is the same, "Beethoven's 5th Symphony performed by the Mars Philharmonic Orchestra." However, the page describes how this clip relates to the drama that Beethoven creates in his 5th symphony and describes a specific rhythm captured in this clip. It goes on to explain how this symphony "crystallized Beethoven's mature compositional innovations."
Example 5: 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"
Example 6: a pair of images used to create a visual effect.
Two images are used to create curved edges on a "tab" interface. The images do not provide information, functionality, or a sensory experience and are marked such that they can be ignored by an assistive technology.
Example 7: an internet radio station.
A radio station broadcasts over the internet. The station's Web site describes the type of music played, a schedule of the shows, and the "current song" is updated each time the DJ starts a new track. Interviews are recorded and published in the archives. Transcripts of the archived interviews are provided per Guideline 1.2 Provide synchronized alternatives for multimedia.
Editorial Note: Does the above example help to clarify level 1 success criterion 5 or does it need additional clarification?
Example 8: a traffic Web camera.
A Web site allows end-users to select from a variety of Web cameras positioned throughout a major city. After a camera is selected, the image updates every 2 minutes. A short text alternative identifies the Web camera as, "TraffiCam." 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 2 minutes.