- From: Eric Hansen <ehansen7@hotmail.com>
- Date: Thu, 29 Jun 2000 02:22:07 EDT
- To: w3c-wai-ua@w3.org
Date: 29 June 2000, 2:11 hrs To: UA List From: Eric Hansen Re: A Proposal for Multimedia-Related Terms I have read Ian Jacob's memo "Thoughts on multimedia and some definitions" [1] and Al Gilman's comments on that memo [2]. I found Ian's memo to provide a good summary of the conversation and issues raised. I have minor comments, mostly about word usage but may communicate them later if warranted. I think I agree with most of what I heard Al saying. In both these memos I see an emphasis on the importance of construct of "message". I think that certain areas of agreement are emerging. This memo proposes a new/refined definition for multimedia related terms. I wish I had more time to explain what I am thinking but I generally feel good about what I have proposed. I think I see light at the end of the tunnel. Essentially, I'd like to expand the definition multimedia presentation to cover a greater variety of presentations and also to give developers of Web content and of user agents greater flexibility in deconstructing multimedia presentations into there constituent parts if necessary for the purpose of developing accessibility content. Objects, presentations, multimedia presentation, auditory presentation, visual presentation, tactile presentation, etc. 1. Audio or audio object - output from an audio viewport [NOTE. I am not certain enough of the "viewport" model to know if this is fully accurate and consistent. Same for the next two sentences. In any case, I think we recognize the importance of this base-level construct that is somewhat divorced from the notion of "message".] 2. Visual object - visual output (may include graphics, texts, and visual portions of movies and animations); output from a visual viewport 3. Tactile object - tactile output (via braille, raised-line drawing, or manipulable) from a tactile viewport 4. Presentation - information intended to deliver a message, i.e., to communicate a coherent body of information to a user. 5. Audio track - an audio object that is intended as a whole or partial presentation. An audio track can, but does not necessarily correspond to a single audio channel (left or right audio channel). 6. Visual track - a visual object that is intended as a whole or partial presentation. A visual track does not necessarily correspond to a single physical or software object. A visual track can be text-based or graphic, static or animated. [This idea of it possibly being static is important and, I think, necessary.] 7. Tactile track - a tactile object that is intended as a whole or partial presentation. This does not necessarily correspond to a single physical or logical track on the storage or delivery media. 8. Audio-only presentation - audio presentation; a presentation consisting exclusively of one or more audio tracks presented concurrently or in series 9. Visual-only presentation - visual presentation (NEW); a presentation consisting exclusively of one or more visual tracks presented concurrently or in series 10. Tactile presentation - a tactile-only presentation; a presentation consisting exclusively of one or more tactile tracks presented concurrently or in series 11. Multimedia presentation - virtually every other kind of presentation, except audio-only presentations and visual-only presentations. Special or legacy terms: 1. Auditory track - an audio track that is part of a multimedia presentation 2. Audio presentation - audio-only presentation 3. Standalone visual track - a visual presentation consisting of one visual track Requirements for Different Types of Presentations 1. Audio-only presentation - provide a text equivalent (text transcript) and captions [captions is implied in WCAG 1.0] 2. Visual-only presentation - provide a text equivalent of the visual track 3. Multimedia presentation - provide auditory descriptions, captions, collated text transcript ==== Some varieties of multimedia presentation are as follows: Heavy Reliance on Both Auditory and Visual Tracks. This kind of multimedia presentation places heavy reliance on both the auditory and visual tracks in order to convey its message. Understanding such presentations typically requires both the visual and auditory tracks and the tracks typically must be closely synchronized. Imagine an instructional multimedia presentation designed to teach how to cook a certain meal. The visual track shows the instructor preparing and heating the ingredients and then arranging the finished items on a platter. The auditory track must be closely synchronized with the visual track since the meaning of the instructors' comments would not make sense to the student unless it was apparent which items were being referred to and at what stage of the process. Most movies and television programs fall into this category. Auditory Track With "Background" Visual Track. This kind of multimedia presentation places heavy reliance on the auditory track and light or negligible reliance on visual track to convey its message. Visual Track With "Background" Auditory Track. This kind of multimedia presentation places heavy reliance on the visual track and light or negligible reliance on the auditory track to convey its message. REFERENCES [1] http://lists.w3.org/Archives/Public/w3c-wai-ua/2000AprJun/0517.html [2] http://lists.w3.org/Archives/Public/w3c-wai-ua/2000AprJun/0520.html ________________________________________________________________________ Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com
Received on Thursday, 29 June 2000 02:22:39 UTC