Web Posted on: December 21, 1998

How Blind Persons Can Access the Audio and Video Formats of the WWW: I-wave, Mpeg Jpeg, Gif--Potholes or Billboards

Douglas Wakefield
Telecommunication Specialist
U.S. Access Board
Washington DC

Judith M. Dixon
Consumer Relations Officer
National Library Service for the Blind and Physically Handicapped
Library of Congress
Washington, DC

Introduction

Until the development of reasonably reliable screen access programs for the Windows operating system, most blind or visually impaired computer users were limited to text-oriented Web browsers. Although many of the text-based browsers give very adequate access to information on the Web, they do not allow the user to enjoy the diverse multimedia presentations pervading the Internet. Today, through the use of Windows, blind and visually impaired people can not only enjoy the variety of audio formats on the Web but also create, edit, and place their on audio files on the Web for others to enjoy.

The Web is also a source of many graphics images. Although it is more challenging to access images as opposed to audio for blind users, graphics are still not totally out of reach. It is possible for a person who can not see the screen to, with limited help from a sighted colleague, create, shape, and place graphics on the Web.

Audio

A discussion of audio on a computer or on the Web can consist of many parts, file formats, audio players, and audio recorders and editors. The subject is complex enough that books have been written on any one of the above subjects. For this discussion, we'll focus on creating, editing, and placing an audio file on the Web.

Creating the audio file

The Windows operating system contains tools that allow the creation a sound file by using the audio card as a recorder. More sophisticated recording systems are built into most audio file editors such as Cooledit, Sound Forge, or FastEdit. A sound file can be created by recording onto the hard disk with a microphone or by taking sounds off of a CD or the Web. The file created will be a wav file. These are the typical sound files used by Windows. When recording a sound file, the user must make some judgement calls. The most important being quality versus file size. It is possible to create a CD-quality stereo file, however, the size for anything over a minute in length will be megabytes. If disk space is available, it is often wise to create as high a quality file as possible and then with an editor convert the file to a lower quality and try playing it. This process can be repeated until a happy balance is obtained.

Editing a Sound File

Depending on the sound file, and how it was created, some editing may be required. Typically, there may be "dead air" at the beginning and end of the file that needs to be trimmed so the sound will begin as soon as the file is loaded. Until fairly recently, the only systems that would allow a person unable to view the screen the ability to accurately perform fine audio edits cost in the range of $10,000. These systems use what is referred to as a hardware controller. The device basically turned the computer into a digital tape recorded with hardware controls to play, record, fast forward, and rewind and do what is called scrubbing, the ability to move the audio back and forth over a record head to find a precise edit point.

The cheaper software editing systems use a wave pattern and edits are made by viewing the wave pattern and making cuts on the visible wave. Today, there are audio editing programs that allow precise editing with keyboard controls. It should be noted that the keyboard controls are generally found in the professional or full versions of these programs, not the low-end versions and may cost up to $200.00.

Putting the file in use

After creating a polished digital recording, most likely in a wav format, the file can be played on a computer or placed on a home page on the Web. The main drawback to placing this type of file on the Web, even if you did have the disk space, is that another person wanting to play the file must download the entire file before it can be played. An alternative is to turn the wav file into something that another user can access with realaudio. This means the file will start playing long before the entire contents have been transmitted. Conversion a wav file to a realaudio file is easy with the use of a shareware converter. The result is a file with the extension of .ram.

Uploading and making your file available for others-- Contrary to popular belief, you do not need a realaudio server to serve up a realaudio file. You can use what is called "http streaming." You'll need to check only one thing with your service provider. Does the service support the mime types associated with realaudio? Here are the instructions for putting your audio file on the Web.

1. Copy your encoded files (files with the .ra, .ram, .rm or .rpm extension) to your Web server.
2. Use a text editor (such as Notepad) to create a metafile containing a URL to your file. For example: www.real.com
3. Save your metafile as a text using a .ram file extension.
4. In your HTML document, reference the metafile in a hyperlink. For example: http://www.real.com/home/welcome.ram
5. When a user clicks on the link, the streaming file(s) begin to download. The RealPlayer begins playing after a few seconds; it does not need to wait for the entire file to be downloaded.

A discussion of graphics

Unfortunately, no one has created a screen reader that will automatically describe a picture. But a blind person can still manipulate images and place them on a home page or convert them into a tactile form. Ironically, many of the image editing programs for Windows have good keyboard access. These programs will allow a person, without viewing the image itself to size, shape, and apply special effects to an image. Most webpage authors place some graphics on pages. As a matter of fact, a webpage without graphics would be considered boring and unappealing. For this reason alone, any blind person creating a personal webpage, or creating a page for others should have some understanding of graphic manipulation.

The initial file

typical graphic files have the extensions of either gif, jpg, bmp, or tif. These files can be found on the Web, on CD-ROM's of clipart or they can be created from a printed page with a scanner. Once the file is on the computer a little testing may have to occur to determine what editor will access it. Lview Pro is a program that can be very useful at this point as it can convert image files from one format to another thus creating a file appropriate for a specific editor.

Shaping the file

Microsoft Photo Editor has features that are very useful for blind computer users, and it is a part of the Office 97 suite. Once the file has been loaded into the editor the Properties selection under the Files menu will show the actual size of the image in inches. Other menu options resize the image and apply special effects such as turning it into an outline drawing, showing the image as a transparency, or sharpening the image. If the file is going to be printed on swell paper to create a raised image, it is often necessary to reverse the image, That is, make the dark areas light and the light dark.

Putting the file to use

As just mentioned, the graphics file can be printed, then copied to swell paper and raised using one of the devices on the market today. It is also very easy to place the graphic on a home page. Making the image available for others to see is much simpler than preparing a realaudio file for retrieval. The image file simply needs to be referenced with an HTML tag in the home page document.