TV stations and multichannel operators must start phasing in video
description of programming during the three-month period beginning April 1.
Stations affiliated with the 'Big Four' networks in the top 25 TV markets
must provide at least 50 hours per quarter of described prime time or children's
programming. The requirement translates to four hours per week.
Cable- and satellite-TV systems with 50,000 or more subscribers have
identical video-description requirements for each of the top five national
nonbroadcast networks they carry.