NEW YORK (AP) - MTV, VH1 and CMT are going back to their roots by showing videos as part of a "Music Independence Day" on the Fourth of July. Van Toffler, who runs the networks for Viacom, said the idea is to give a boost to musicians at a time of trouble for the industry and provide soundtracks for the parties and gatherings people are having at home. The networks said Wednesday they will let little-known artists compete for airtime. The networks got their start primarily airing music videos but switched to other, more lucrative programming over the years. The Fourth of July special can also give the networks a boost since the first week of July is traditionally the least-watched TV week of the year, because so many people are outside.