Descriptive Video Service

The Descriptive Video Service (DVS) is a major United States producer of video description, which makes visual media, such as television programs, feature films and home videos, more accessible to people who are blind or otherwise visually impaired. DVS often is used to describe the product itself.

In 1985, PBS member television station WGBH-TV in Boston, Massachusetts, began investigating uses for the new technology of stereophonic television broadcasting, particularly multichannel television sound (MTS), which allowed for a third audio channel, called the Secondary Audio Program (SAP). With a history of developing closed captioning of programs for hearing-impaired viewers, WGBH considered the viability of using the new audio channel for narrated descriptions of key visual elements, much like those being done for live theatre in Washington, D.C., by Margaret Pfanstiehl, who had been experimenting with television description as part of her Washington Ear radio reading service.

After reviewing and conducting various studies, which found that blind and visually impaired people were consuming more television than ever but finding the activity problematic (often relying on sighted family and friends to describe for them), WGBH consulted more closely with Pfanstiehl and her husband, Cody, and then conducted its first tests of DVS in Boston in 1986. These tests (broadcasting to local groups of people of various ages and visual impairments) and further study were successful enough to merit a grant from the Corporation for Public Broadcasting to complete plans to establish the DVS organization permanently in 1988. After national testing, more feedback, more development of description technique, and additional grants, DVS became a regular feature of selected PBS programming in 1990. Later, DVS became an available feature in some films and home videos, including DVDs.

...
Wikipedia