Surround Formats Proliferate On HD Discs

NEW YORK — A multitude of sound-track formats, including losslessly compressed Dolby TrueHD and DTS HD Master sound tracks, have been appearing on Blu-ray and HD DVD discs, according to two Web sites that compile data about high-definition discs released in the U.S. market.

One of the sites also found multiple Blu-ray titles with 6.1- and 7.1-channel sound tracks,

By the end of January, 192 of 460 Blu-ray titles marketed in the United States carried uncompressed PCM sound tracks, with 41 carrying lossless Dolby TrueHD, 124 carrying Dolby Digital, and two carrying Dolby Digital Plus, according to www.blu-raystats.com. A total of 69 carried lossless DTS HD Master, 21 carried DTS HD High Resolution, and 22 carried DTS. Seventeen of the Blu-ray titles carried 7.1-channel sound tracks, and 13 carried 6.1.

Discs can contain multiple sound tracks, each in a different format.

Among about 400 U.S.-market HD DVD discs, 90 carried Dolby TrueHD, 336 carried Dolby Digital Plus, eight carried DTS HD High Resolution, one carried DTS HD Master Audio, and 23 carried DTS, sister Web site www.hddvdstats.com reported.

The sites, which generate income from referrals to Amazon.com, don't report the sampling rates or bit depths of the sound tracks.

Officially, 454 Blu-ray titles were available by the end of January in the U.S. market, up from the year-ago 135, according to the Blu-ray Disc Association. More than 400 titles were available at the end of January in the HD DVD format, excluding another 600 titles released in other countries but available on-line to U.S. consumers and playable on U.S.-market HD DVD players because the disc format lacks regional coding, according to the HD DVD Promotion Group, which reported these numbers prior to Toshiba's decision to drop the format. Members of both groups include movie studios, disc makers and player manufacturers (see complete coverage, p. 1).

All told, more than 854 HD DVD and Blu-ray Disc titles were available as North American releases by January 2008, up from 260 in January 2007.

Both disc formats support multiple "mandatory" and multiple optional surround formats (see table). Discs need feature only one of the multiple mandatory sound-track formats, but in the interests of compatibility, players must be able to decode all mandatory formats. Players and discs also have the option of incorporating one or more optional surround formats.