Web Posted on: February 6, 1998

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.

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.

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.