- From: Gregg Vanderheiden <gv@trace.wisc.edu>
- Date: Thu, 17 Apr 2003 16:20:09 -0500
- To: w3c-wai-gl@w3.org
- Message-id: <013801c30527$200ef360$ac17a8c0@TOSHIBATABLET>
At the teleconf call it was pointed out that it looked unbalanced to ask that background images be removable but not background sounds (at the upper levels) It was pointed out the guidelines was "text presented over graphics" . With sound, the speech is not mixed with the background by the author. So it would not be possible to turn off the background sounds from any speech unless the speech was in a separate sound track than the background sounds. In that case they would be removable anyway. So it was determined that requiring that speech be separated from background sounds would make all mixed audio presentations (including all movies, animations, live broadcasts etc) might be prohibited. Our decision was therefore to not put requirements in the higher levels for speech to be separable from background sound - nor to require that there be specific separation between speech and background. There are captions that can be used for those who can see and cannot hear well. We also decided to add a note in the benefits section to reflect this difference. I took an action item to try to do this. My attempt is below. 1.5 Benefit #2 Speech over background sounds Because speech is often naturally mixed with background sounds (movies, live news etc) and cannot be easily removed or separated, captions are provided (under checkpoint guideline 1.2) to make dialog understandable. However not all people can see or read the captions. Where speech is mixed or recorded so that it is at least 20 db above any background sounds people do not need to rely on captions to understand the dialog. Gregg -- ------------------------------ NOTE: TRACE HAS MOVED TO A NEW ADDRESS (Same Email and Phone) Trace R & D Center 2107 Engineering Centers Bldg. 1550 Engineering Drive MADISON, WI 53706 ------------------------ Gregg C Vanderheiden Ph.D. Professor - Human Factors Depts of Ind. Engr. & BioMed Engr. Director - Trace R & D Center University of Wisconsin-Madison Gv@trace.wisc.edu < <mailto:Gv@trace.wisc.edu> mailto:Gv@trace.wisc.edu>, < <http://trace.wisc.edu/> http://trace.wisc.edu/> FAX 608/262-8848 For a list of our listserves http://trace.wisc.edu:8080/mailman/listinfo/
Received on Thursday, 17 April 2003 17:24:04 UTC