Biomedical Engineering Reference
In-Depth Information
Closed Captioning
effects, into written text. Captions can be
open
or
closed
; open captions are always
visible on a screen, while closed captions
are embedded in the broadcast signal and
must be accessed with dedicated equip-
ment to be seen. Captions can be added to
prerecorded video such as television pro-
grams and movies. Captioning can also
occur during live events, such as a face-
to-face workshop, conference, television
newscast, or sporting event on television,
with the use of Communication Access
Realtime Translation (CART). Making
the spoken word available as text immedi-
ately through CART developed out of the
court reporting industry. The purpose of
court reporting and CARTing, insofar as
is possible, is to type a verbatim transcript
of speech at various events, for example
a deposition, conference speech, or class.
A verbatim transcript is possible because
this typing is performed on a shorthand
machine, called a stenotype, that has 22
keys, including numbers (Figure 11-1).
The CART writer depresses one or more
keys simultaneously which documents
the speech sounds being uttered. A soft-
ware package converts that shorthand
phonetic representation to text in real
time through an internal dictionary.
A person who is trained as a captioner or
CART writer must type at least 180 words
per minute with high accuracy, and many
individuals can type 200 to 225 words per
minute. As is seen later, CART is one of
several captioning services available.
Many entities across the country
offer the service of adding captions to pre-
existing video. The Described and Cap-
tioned Media Program maintains a list
Today, more television programming
than ever before is available with caption-
ing in which the dialog appears as text on
the screen, along with words to convey
audible events such as music, laughter,
and sound effects. Captioning used on
television and in films can be benefi-
cial to individuals who are deaf or hard
of hearing, people learning English, and
viewers in areas with high background
noise. Captioning for recorded television
programming was first developed in the
early 1970s and over the course of the
next decade was expanded to include live
television events. Since the 1980s, the U.S.
Congress has passed several laws improv-
ing the availability and required uses of
captioning. These laws include the Televi-
sion Decoder Circuitry Act of 1990, the
Americans with Disabilities Act of 1990,
the Telecommunications Act of 1996, and
the Twenty-first Century Communica-
tion and Video Accessibility Act of 2010.
These laws, combined with an increase in
voluntary captioning, have helped foster
an explosion of captioning accessibility.
However, not all programming and ven-
ues are captioned, and consumer groups
and others are continuing to push for cap-
tioning accessibility.
Captioning Basics
Captioning is transcribing or translat-
ing sound, whether that sound is spoken
words, music, music with lyrics, or sound
