Media Accessibility Checklist

• Always record the alternative content (the best default option, since a resource recorded by one user may later be accessed by another different user who may have different and unanticipated requirements);
• Record the alternative content only if it is active at the time of recording;
• Ask at recording time whether to record the alternative content;
• Never record the alternative content.)

1. the alternative content's extent is specified in relation to the media viewport (e.g., picture-in-picture video, lower-third captions)
2. the alternative content has its own independent extent, but is positioned in relation to the media viewport (e.g., captions above the audio, sign-language video above the audio, navigation points below the controls)
3. the alternative content has its own independent extent and doesn't need to be rendered in any relation to the media viewport (e.g., text transcripts)

If alternative content has a different height or width than the media content, then the user agent will reflow the (HTML) viewport.

1. text scale (i.e., the general size of text) ,
2. font family, and
3. text color (i.e., foreground and background).

1. the bounding dimensions and coordinates of rendered graphical objects;
2. font family;
3. font size;
4. text foreground color;
5. text background color;
6. change state/value notifications.