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Member of:
 ISOC
 IWA
 ARTT
 RTS
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Provide user controls
![[Layout with navs on left]](images/2qt_cntl.gif)
Give users the following types of
controls for all playable files: Play, Pause/Resume, Stop,
Rewind, Fast Forward and Volume. QuickTime video and sound
files automatically provide these controls. If you use other
types of media formats, you may need to design the controls
yourself. Animated GIFs are usually presented with no user
controls. In general, provide Play and Stop functions by
using a scripting language.
Provide text equivalents for visual
and auditory content
To make your site accessible to users
with vision and hearing impairments, provide text and/or
audio descriptions of visuals, and transcripts
(word-for-word text versions) plus descriptions of audio
content. Many people cannot use video, images, or sound, but
they can use equivalent information provided via other
media. The equivalent text or audio descriptions should
convey the same information as the video or audio content.
Use the right technique for providing
accessible multimedia:
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For images and animation, use alt text
to provide a brief description, and the longdesc attribute
to provide explanations longer than a sentence or two.
Longdesc provides an invisible link read by screen readers
to a detailed description located on a different Web page.
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For audio and video, provide a
hyperlink to a trascript plus a description near the play
button or link to the clip. Descriptions should generally
be longer than transcripts because they need to descibe
the setting and action.
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For Java applets, provide alt text, and
if the applet uses the OBJECT element, provide text
descriptions within the element.
Inform users of the content and size
of media objects
 ![[sample download message]](images/download.jpg)
Instructions for downloading media objects should include
the file size, the media type, and a description of the
subject matter. For video clips, you can provide a static,
interlaced thumbnail image with alt text for screen readers.
This information will help users determine whether they want
to wait for the download.
Use animations to attract attention
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![[example of how animation draws attention]](images/2look.gif) |
Movement attracts the
eye. If you draw attention to an element by making it
move, you may cause it to seem more important than
surrounding images which remain still. If you place
animated images near still text, be careful that the
animations do not distract the reader. And if you
animate text, make sure you control the timing and test
to make sure that the text is still readable. |
Create animations that enhance
explanation
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Some animations are
used to entertain, but you can also use them to explain.
They are particularly good for explaining ideas
involving changes in time, position, and/or process. |
Use repetitive loops sparingly
Animation or sound loops are efficient
because they can run continuously without adding to file
sizes. However, they can become irritating or distracting.
Knowing how to design a media loop well requires judgment
and sensitivity to the situation. Test to make sure that
users are comfortable with your media loops and consider
enabling users to stop the loop. | |
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