San Francisco - Surround sound in 7.1 channels has moved from movie theaters and Blu-ray discs to a streaming service for the first time.

Vudu, the subscription-free, VOD movie service owned by Wal-Mart Stores, has begun streaming Disney's "Pirates of the Caribbean: On Stranger Tides" in Dolby Digital Plus 7.1.

Vudu has been streaming select content in 5.1-channel Dolby Digital Plus for several years, Dolby said.

Netflix also streams select titles in Dolby Digital Plus 5.1, as have a number of traditional terrestrial-TV broadcasters, IPTV services, cable operators, and direct broadcast satellite service, Dolby said.

For theaters, more than 30 movies have been released in 7.1-channel Dolby surround sound.