Descriptive Video Service
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The Descriptive Video Service (DVS), created by WGBH-TV in Boston [1], is used by the Public Broadcasting Service (PBS) in the U.S. to provide video description for the visually impaired, so they can better understand what is happening on the video portion of the program. This greatly improves the experience and makes it much more valuable to blind and visually impaired viewers.
An example might be on a program about Old Faithful in Yellowstone National Park. As the geyser starts, the DVS announcer would describe the scene:
"Boiling water bubbles up from the hole in the middle of the flat ground, and quickly begins shooting into the beautiful cobalt blue sky above it. The 100-foot tall stream sprays water and steam downwind, until it begins to gradually subside and retreat back into the earth."
While this may be obvious to those who can see the screen, these details must be described to those with vision impairments, which is the purpose of DVS. The DVS announcer is usually the opposite gender of the main announcer, to eliminate potential confusion between the two.
DVS is accessible on any TV with multichannel television sound (MTS) on the second audio program (SAP) setting. When DVS programming is not being transmitted, the local National Public Radio station (or state NPR network) is often heard instead.
DVS programming on television was introduced in 1990 and grew steadily over the next decade. A number of PBS programs and some commercial television programming (such as The Simpsons) used DVS. However, a federal court ruled in 2002 that the Federal Communications Commission had exceeded its jurisdiction by requiring broadcasters in the top 25 markets to carry video description. Since that time, the amount of new DVS programming has declined, and WGBH has withdrawn from supporting the service. It no longer updates its web page and ceased publication of its electronic guide to upcoming DVS programs in early 2005.
DVS audio tracks appear in select DVD movies. Some cinemas also make DVS available, usually in conjunction with Rear Window Captioning.
