Here's another paper from the technology conference sponsored by the
California State University at Northridge and held in Los Angeles earlier
this year.
kelly
| CSUN 98 Papers |
How Blind Persons Can Access the Audio and Video Formats of the WWW: I-wave,
Mpeg Jpeg, Gif -- Potholes or Billboards
Judith M. Dixon
Consumer Relations Officer
National Library Service for the Blind and Physically Handicapped
Library of Congress
Washington, DC
Doug Wakefield
Arlington, VA
Introduction
Computer systems today bear little resemblance to the "Word
Processors" of just a few years ago. Today, the key word for most
computers, especially those targeted at the home market, is
multimedia. Even today's business market systems come equipped with
video and sound capabilities aimed at enhancing business
presentations. Modern-day ads for computers often read as follows:
Super multimedia system breaks all video and sound barriers, includes
megabase surround sound system, advanced graphics display
capable of running all digital video disk presentations.
For many blind computer users the important question becomes, What
part, if any, of all this multimedia hype can be enjoyed or utilized
if one can not see the screen? The answer seems to be a mix of good
and bad news. Many of the sound features incorporated into modern
computers can be enjoyed and, more importantly, manipulated by
visually impaired computer users. But some of the sound editing
capabilities of computers are not accessible to blind users. On the
other hand, at first glance it is often thought that enjoying or
manipulating graphical representations is not within the capability of
blind computer users. As a matter of fact, most publications focusing
on Windows access for blind people generally skip over programs such
as Paint and Imaging. Yet, both can be of great assistance in helping
a blind computer user prepare graphic material for a tactile display.
In the following paragraphs we will focus on how blind computer users
with a minimum of assistance from a sighted colleague can manipulate
sounds and graphics. It is necessary to point out that in the DOS
environment everyone, sighted or blind, has limited access to
multimedia events. It is possible to find DOS graphics viewers and
DOS-based sound playing software. For the most part, however, these
are difficult for everyone to operate, and their capabilities are
quite limited. Therefore, the focus in the rest of this paper will be
placed on programs that run in the Windows 95 environment. Even the
Windows 95 version of the text-based browser Lynx, has multimedia
capabilities not present in its DOS cousin.
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Sound
A discussion of audio on a computer can be divided many different
ways, file formats, audio players, sounds on or off the web, etc. Due
to limits in space we'll focus here primarily on just a few sound
features that may be of interest to blind and visually impaired
computer users.
File formats
Basic to enjoying computer-based audio is knowing just a little about
sound file formats and what players to use with each format.
File types are identified by the file extension, .AU, .AIF, .AIFF,
.MID, .SND and .WAV being among the most common. A few other format
types can signify a file that may be both audio and video, .MPG .RA,
.RAM and .ASX. Of course, .MOV, (movie) files may or may not contain
sound. Files with the .WAV extension are the most common sound files
on a computer as they provide the basic sounds for Windows. They are
also easily created with the sound recorder that comes with Windows.
When you're talking about sound on the Internet, you've got three
basic kinds of sound files:
* Digital audio files. These are usually .WAV files, though you
occasionally see .AU files and some of the other formats such as
MPEG 1 and 2. These files like those in the media folder on your
computer, are just like tape recordings of music or sound effects.
These digital audio files are easily placed and referenced on web
homepages, and are also quite easily manipulated by programs such
as Cool Edit. The blind computer user can record individual .WAV
files and append files to create interesting montages. The actual
editing of .WAV files by blind computer operators is however an
elusive goal and can only be accomplished with the use of very
expensive systems ranging in price from $6,000.00 and up.
* Streaming digital audio. This could as easily fall under the first
category, but since there's so much activity in this area, and
since the way you play these files is so different from
downloading and playing, it deserves to be treated as a separate
category. RealAudio by RealNetworks, formerly Progressive
Networks, is the file format that's gotten the most attention on
the web lately. The advantage of streaming audio is that you can
start listening almost as soon as the file starts downloading. The
ultimate in streaming audio is the ability to listen to live audio
feeds on the Internet. Players for streaming audio include
RealPlayer Plus, Netshow, and Truespeech.
For users of adaptive equipment this form of audio poses more
technical than interface trouble. The ongoing decompression of
streaming digital audio taking place in the computer places heavy
demands on system resources. A computer operating with a speech,
braille, or large print system loaded and running, will need more
memory and power to play streaming audio than the usual
recommended.
* MIDI. The Musical Instrument Digital Interface, standardized by
the MIDI Manufacturers Association, is another type of audio
format that is favored by musicians. Although you may encounter
MIDI on the Internet or as special sounds on a computer, digital
audio will be far more common for the nonmusician.
In summary, for users of speech, braille, and large print, creating
audio files, adding special effects, or appending one file to another
pose no special problems. The one area that is still unsolved for all
but the professional audio person is access to digital audio editing.
At present, all inexpensive systems for editing audio of which we are
aware rely on the user watching a waveform on the screen and making
editing choices by moving a pointer to a particular spot in a wave
pattern.
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Graphics
It is commonly believed that blind computer users will be unable to
manipulate computer graphics. Therefore, most keyboard reference
guides developed for blind computer users, omit chapters on programs
such as MS Paint and Imaging. In reality, MS Paint has more keyboard
alternatives than most other Windows programs and graphics can easily
be manipulated by a blind computer user.
It is true that at present there is no screen reader that can "look"
at a graphic on the screen, interpret it, and describe it to the user.
However, the blind user can gain enough information from these
graphics manager programs to output the graphic in a form more
accessible than simply displayed on the screen.
Once a graphic is printed on paper it can become accessible to a blind
person. First, those people proficient at using the Optacon will have
immediate access to the printed graphic. The Optacon can be used to
examine graphics on a screen, but, there are often many issues that
complicate this procedure. These issues include the scan rate of the
monitor, whether the image is displayed in inverse video, and the
flatness of the screen. Using an Optacon to read or examine a graphic
on paper is much easier than trying to read the computer screen.
It is also possible to take the process of making graphics access one
step beyond the initial printing by copying the printed page onto
swell paper and producing a raised graphic. The last approach has
become quite practical in the last few years due to the development of
low-cost machines that can cause images on the swell paper to raise
up.
Computer images come in many formats, .GIF .BMP, .PCX etc. MS Paint
and Imaging will not handle all formats. A viewing utility such as
Lview Pro allows one to import an image of one format and convert it
to another. This is very important since a prime source of images is
the Internet and the most dominant format on the Internet is .GIF. The
.GIF format can not be handled by the Paint program. Lview can be used
to convert a .GIF to something compatible with Paint.
There are two main operations where Paint or Imaging can be very
useful. First, is the sizing of the image. By simply using the zoom
feature in these programs, it is possible to enlarge or rotate an
image so that many of its details become tactually discernible.
Second, it may be necessary to reverse the image, which can be done in
Paint, that is, change dark areas to bright and vice versa. The swell
paper raises up to produce a tactile graphic when heat is applied to
darkened areas. Therefore, it is often necessary to determine whether
one wants to create raised lines from the darkened areas of a graphic
or the lighter areas. Sometimes, the only way to find the answer comes
from trial and error.
The fact that something can be done doesn't always mean it's a
practical thing to do. It is necessary to raise the question, do blind
people have a reason to use the various steps just described. In fact,
there are many occasions when the ability to produce a tactile
representation of a screen image can be very useful. Some examples
include, producing a section of a subway map either in one's own city
or in a city one is intending to visit, outline maps of most city
subway systems are readily available on the Internet; it is also very
useful when one is traveling to print out just a simple outline map of
a state or county so some perspective of where various places are
located can be gained. Parents of blind children can make extensive
use of raised computer-generated graphics to enhance descriptions of
numerous objects from maps to shapes of animals.
The list of possibilities is only limited by the human imagination. It
may not be practical for everyone to own an $800.00 machine to produce
graphics, but certainly in many offices, schools, and in many homes
the ability to easily produce a tactile image is of great value.
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