glossary entry for “alternative content”

Here are some comments on the glossary entry for “alternative content” in the current editors’ draft of UAAG2. My comments are embedded below and start with “[EH”.

alternative content
      Web content<http://www.w3.org/WAI/UA/UAAG20/> that is used in place of other content that some people are not able to access. Alternative content fulfills essentially the same function or purpose as the original content. WCAG 2.0 recognizes several general types of alternative content:
•       text alternatives [EH: Should be singular alternative; that would help it match media alternative]for non-text content: Text that is programmatically associated with non-text content<http://www.w3.org/WAI/UA/UAAG20/> or referred to from text that is programmatically associated with non-text content. For example, an image of a chart might have two text alternatives: a description in the paragraph after the chart and a short text alternative for the chart indicating in words that a description follows.[EH: I find this phrase confusing: “referred to from text that is programmatically associated with non-text content”. It was not obvious to me that your example addressed this. My revision: “Text that is either (a) programmatically associated with non-text content<http://www.w3.org/WAI/UA/UAAG20/> or (b) referred to by such text. Sometimes both kinds of text alternatives occur together. For example, an image of a chart might have two text alternatives – one of each kind: (a) a short text description that is programmatically associated with the chart (e.g., alt text) and (b) a description in the paragraph that is referred to by the short text description.”]
•       alternatives[EH: Should be singular alternative; that would help it match media alternative. Also this does not match the WCAG2 definition of “alternative for time-based media” which by my understanding refers to only to the “correctly sequenced text descriptions of time-based visual and auditory information that also is capable of achieving the outcomes of any interactivity in the time-based presentation.” Thus this is a considerable expansion the meaning of the term.] for time-based media: Web content<http://www.w3.org/WAI/UA/UAAG20/> that serves the same function or purpose as one or more tracks in a time-based media presentation. This includes: captions<http://www.w3.org/WAI/UA/UAAG20/>, audio descriptions<http://www.w3.org/WAI/UA/UAAG20/>, extended audio descriptions<http://www.w3.org/WAI/UA/UAAG20/>, sign language interpretation as well as correctly sequenced text descriptions of time-based visual and auditory information that also is capable of achieving the outcomes of any interactivity in the time-based presentation.
•       media alternative for text: Media that presents no more information than is already presented in text (directly or via text alternatives). A media alternative for text is provided for people who benefit from alternate representations of text. Media alternatives for text may be audio-only, video-only (including sign-language video), or audio-video.[EH: I suppose it makes sense to include this for completeness, though I don’t think the term is used in the document. Also, I am puzzled by the reference to “Media that presents no more information than is already presented in text”: In other words it puts no lower bound on the info provided. Yet it matches WCAG2 so I guess I am okay with it.]


Eric G. Hansen
Research Scientist
Center for Validity Research, MS 10R
Educational Testing Service
Princeton, NJ 08541
609-734-5615
For more resources see:
ETS Accessibility Research <http://www.ets.org/research/topics/assessing_people_with_disabilities>
Accessibility Information & Resources<https://sharepoint.etslan.org/rd/ctrvalres/AIR/default.aspx> (ETS internal only)






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