When we think of video accessibility, we usually go straight to captions. But when the Twenty-First Century Communications and Video Accessibility Act (CVAA) was
signed into law in 2010, it had a requirement
that most video covered by Section 508 also be
accessible to users who are blind. It is noteworthy that the updates to Section 508 that take effect in January 2018 clarify that internal-facing
educational and training videos are not exempt.
Suppose a teacher who is blind needs to play
a video projected on a screen for the class. For
this to work, the video player needs a user interface with which the teacher can easily interact, one with properly labeled inputs and status
reports. Fortunately, this has largely become
the norm over the past 5 years.
The more difficult scenario is where the student who is blind needs to learn from an educational video, since equivalent content is also
needed for the motion picture track. The standard solution for providing that equivalent content since the 1970s has been Audio Description
(AD), an additional channel of audio narration
during natural pauses in the video’s native audio. In theaters, that channel is usually delivered
wirelessly to special headsets; on television, it’s
commonly on the SAP track. In streaming media, it’s either “burned-in” to an alternative version of the video file or else delivered as text (in
a variant of Web Video Text Tracks, known as
WebVTT, or Timed Text Markup Language, or
TTML). The text-based method is preferable: Everyone benefits from the AD metadata since indexing and discoverability are accommodated.
Audio that describes educational video is incredibly difficult to create, and thus very rare.
An educational video is informationally dense;
the visual aids tend to be highly detailed, and it’s
ambiguous as to what in them is relevant. Long
pauses in the lecture audio, during which the
visuals can be described without interference,
are abnormal. Contrast that with an entertainment film where lingering establishing shots are
frequent and dialog is scripted to be sparsely
meaningful. Even given those advantages, audio
describing entertainment film requires specialized training and poetic talent as well.
In order to fit adequately informative audio
description into an educational video, “
extended audio descriptions” are typically required,
where the video is paused in order to make
space for the description. This is a necessary
evil that requires deliberate restraint; there is
a limit to how much more patience and stamina can be demanded of students who can’t see
the motion picture content well enough to learn
from it. It ought not to take twice as long to
watch a video due to frequent pauses for extended descriptions.
Strictly speaking, audio description is not required—equivalent content is—and we’re free
to tinker to find what best meets our students’
and teachers’ needs. Suppose our streaming
media is a 360° video. Were we to rely on traditional audio description, would we want a
different description track for each 90° of the
video? Each 45°? Each 30°? Would that decision
be arbitrary, or based on how the target student would best learn from the 360° video?
Upping the ante, how do we provide equivalent content for the visual component of a virtual reality simulation? Does it make sense to tack
on descriptions of what the student who is blind
is missing in certain predictable orientations?
Rather, should we reconsider our foundational
assumptions about how to structure these synthetic experiences to make them even more satisfyingly informative than the real world usually
is to a student who is blind?
My point is not that audio description is a bad
thing. It’s wonderful for entertainment media
and some educational video. I am, however, unconvinced that it’s usually the best implementation for providing equivalent content for the
visual aids we use in educational media, especially when looking to the future. We may need
to come up with new technologies that better
meet our students’ needs.
The Challenge of Audio
Description for Education
Liam Moran ( email@example.com) produces curricular digital
media and manages the servers to store, process, and deliver
it at the Center for Innovation in Teaching and Learning at the
University of Illinois–Urbana-Champaign.
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