1.1.3 Time-Based Media Alternatives (small revisions)

1.1.3 Time-Based Media Alternatives: The user can configure any or all of the
following for visually-rendered time-based media alternatives (e.g. captions,
sign language video):

(a) Scale the visual media alternative as a viewport that may occupy any
rectangular region within the user agent's viewport.

(b) Position the visual media alternative as a viewport so that it does not
obscure the primary time-based media or its controls.

(c) Adjust Text within Alternative media tracks in conformance with 1.4.1.

The user can scale and position alternative visual media tracks independent of
the base video or audio player presentation. (Level AAA)

Intent of Success Criterion 1.1.3 :

Users who require or can benefit from  alternative media tracks in video or
audio may not find the default or authored position and size of those tracks to
be usable. Enabling the user to move and scale any displayed alternate media
tracks (e.g. captions) allows for the displayed content to be positioned and
sized to meet the needs of the user.

Examples of Success Criterion 1.1.3 :

Justin has low vision and works in a noisy environment that makes it difficult
to listen to instructional videos. When he enlarges the text of the captions to
a viewable size, they block most of the video image. Justin selects an option
that displays the caption track in a separate window, which he positions below
the video image so the captions do not block the video image.

Jaime is deaf and is taking courses from on online university. She prefers to
utilize ASL if it is available for online media, and a current course she is
taking offers both captions and a signing avatar for the recorded lectures.
Selecting the signing track, she finds the  default size of the avatar window too
small, making it difficult to follow. The avatar also overlays an important part
of the lecture video content. Jaime drags the avatar out of the video player
and enlarges it, so that both are equally sized and side by side.

Related Resources for Success Criterion 1.1.3 :