Multimedia Accessibility and Captions
Required Readings
The readings for this lesson include the following parts of the WebAIM web site:
- Captions: Read at least the "Web captioning overview" at http://webaim.org/techniques/captions/ and "Software for creating captions" at http://webaim.org/techniques/captions/software.php. If you have experience or an interest in multimedia, you should read as much as you can in this area.
- Flash: Read at least the first section: "Creating accessible Macromedia Flash content" at http://webaim.org/techniques/flash/. If you use Flash on your website, or if you plan on using Flash in the future, you should read the full chapter.
Captioning Main Points
Again, there is much more information in the readings, but here are some basic points:
- Captions allow people who are deaf to access video and/or audio content.
- Also, anyone who views web videos can benefit from captions, for example if the dialogue is hard to understand, if the audio quality is poor, if the user does not have speakers (such as when using a computer in a library or other public area), etc.
- "Closed captions" must be turned on (such as the captions on your TV set); "open captions" are always on and cannot be turned off. Either method is acceptable from an accessibility standpoint, although some users don't know how to turn on the captions in their media players. (See the "Introduction to captioning for Windows Media Player" for instructions on how to turn on captions in Windows Media Player, for example.)
- Every media player creates captions in a slightly different way, so if you put video on the web in more than one format, you'll have to learn the various methods for each player.
- Unlike captions for TV, there are no technical standards for web captions... yet. Perhaps someday one of the professional captioning associations will standardize web captions. But until then the unofficial "standard" is to use white Arial or Helvetica text—12 to 16 point font—on a black background, and to place the captions at the bottom of the video.
- The most time-consuming part about creating captions is typing the text transcript. It can take 3 to 6 hours or more to type up the text for every hour of dialogue.
- A text transcript should always be provided as an alternative to the captioned video. This benefits several groups of people, most notably those who are both deaf and blind, since they would need a text version of the video. (Individuals who are deaf and blind usually use screen readers, but the output is converted into refreshable Braille, rather than to sound.
Flash Accessibility Main Points
You will read more details about Flash accessibility in the readings, but here are a few of the main points to keep in mind:
- Flash can can be a wonderful tool for creating engaging content, especially for people with cognitive disabilities
- Flash can be accessible to screen readers, but only under certain conditions,
including the following:
- The user must have the Flash player
- The Flash player must be a recent version (older players don't support the accessibility features)
- The user must have a screen reader
- The screen reader must be a recent version (older versions don't support the accessibility features)
- The creator of the Flash content must have designed the Flash content with accessibility in mind. Usually this means adding accessibility features on purpose (the default accessibility status of Flash objects is very poor), and testing it with a screen reader.
- The Flash object must be keyboard-accessible
- If there is dynamic content, every step of the process must be accessible. This is usually not easy. In fact, many designers give up and do the following:
- Provide an HTML alternative if it is too hard to make the Flash object directly accessible.
