Қос жақты оптикалық диск: DualDisc туралы мәліметтер

Double sided optical disc

The DualDisc is a type of double sided optical disc product developed by a group of record companies including MJJ Productions Inc., EMI Music, Universal Music Group, Sony BMG Music Entertainment, Warner Music Group, and 5.1 Entertainment Group and later under the aegis of the Recording Industry Association of America (RIAA). It featured an audio layer intended to be compatible with CD players (but too thin to meet Red Book CD specifications) on one side and a standard DVD layer on the other. In this respect it was similar to, but distinct from, the DVDplus developed in Europe by Dieter Dierks and covered by European patents. DualDiscs first appeared in the United States in March 2004 as part of a marketing test conducted by the same five record companies who developed the product. The test involved 13 titles being released to a limited number of retailers in the Boston, Massachusetts, and Seattle, Washington, markets. The test marketing was seen as a success after 82% of respondents to a survey (which was included with the test titles) said that DualDiscs met or exceeded their expectations. In addition, 90% of respondents said that they would recommend DualDisc to a friend. However, sales plummeted over the next three years, particularly in competition with rival formats like SACD and DVD A discs. DualDisc titles received a mass rollout to retailers throughout the United States in February 2005, though some titles were available as early as November 2004. The recording industry had nearly 200 DualDisc titles available by the end of 2005 and over 2,000,000 units had been sold by the middle of that year.

Record companies had two main hopes for DualDiscs; the first being that they would eventually replace CDs as the preferred media for purchase at music retailers, and the second that the inclusion of bonus DVD content at a price similar to a conventional CD would help to slow down online music piracy by giving consumers more incentive to buy their music through retailers. Some titles such as Devils & Dust by Bruce Springsteen and Straight Outta Lynwood by "Weird Al" Yankovic have been released in the United States exclusively as DualDiscs.

In the United States, the cost of a DualDisc at retail versus that of a conventional CD varied depending on the title but, on average, a DualDisc cost about $1.50 to $2.50 USD more than the same title on CD. Some DualDisc titles such as Mr. A Z by Jason Mraz and In Your Honor by the Foo Fighters had enhanced packaging which increased the retail cost of the DualDisc version of the albums over their CD counterparts more than the average. There were also other factors which go into the additional costs such as production, marketing etc.

The CD side of a DualDisc contained standard 16 bit LPCM audio sampled at 44.1 kHz. On the DVD side, most record companies (with the notable exception of Sony Music: see below) provided the album's music in both high resolution, 24 bit DVD Audio (typically at a sample rate of 96 or 192 kHz for stereo and 48 or 96 kHz for surround sound) and lower resolution, 16 bit Dolby Digital sound (typically sampled at 48 kHz). This was done to allow consumers with DVD Audio players access to very high resolution stereophonic and/or surround sound versions of the album, while also providing the lower resolution Dolby Digital stereophonic and/or surround sound which is compatible with any DVD player.

Because Sony had an existing high resolution audio format, SACD, in the marketplace which directly competes with DVD Audio (see next section), Sony Music, as a general rule, only provided 16 bit, 48 kHz sampled LPCM stereophonic (and sometimes Dolby Digital Surround) sound on the DVD side of their DualDiscs. The sound was compatible with any DVD player; however, it does not provide the higher fidelity and resolution of 24 bit, high sample rate DVD Audio. In addition, several SonyBMG titles whose regular editions include copy protection programs (such as XCP and SunnComm) did not feature the software on the DualDisc versions.

The biggest competition to DualDisc was the hybrid Super Audio CD (SACD), which was developed by Sony and Philips Electronics, the same companies that created the standard CD. DualDiscs and hybrid SACDs were competing solutions to the problem of providing higher resolution audio on a disc that can still be played on conventional CD players. DualDiscs took the approach of using a double sided disc to provide the necessary backwards compatibility; hybrid SACDs are a one sided solution that instead use two layers: a conventional CD layer and a high resolution layer. Hybrid SACDs claim a higher compatibility rate with conventional CD players than DualDisc, because hybrid SACDs conform to Red Book standards. However, a SACD or SACD capable DVD player is required to take advantage of the enhanced SACD layer. With a DualDisc, consumers could use their existing DVD player to hear surround mixes. (DVD Audio capable players are required for higher resolution audio, if present.) In 2005, it was estimated that 75% of households in the United States have at least one DVD player.

There are numerous criticisms about DualDiscs, ranging from size to DualDiscs being more fragile than conventional CDs.

A number of electronics companies such as Lexicon, Marantz, Mark Levinson, Onkyo, Panasonic, Pioneer, and Sony (both its Computer Entertainment and Electronics divisions) issued statements warning consumers about possible problems with playing DualDisc titles on their equipment. These warnings ranged in severity from DualDiscs simply not working with the equipment to actual damage to the disc and/or equipment. Meridian Audio, Ltd., on the other hand, issued a statement that "no harm or damage whatsoever" would be caused to the player or the disc if DualDiscs were used on their equipment, but noted that their players with DVD drives would not reliably play the CD layer.

There was some controversy surrounding the DualDisc format, as Dieter Dierks, the inventor of the DVDplus specification, claimed that DualDisc technology is in violation of his European patents. This delayed the release of DualDisc titles in Europe, with them eventually hitting European shores in September 2005. The first British artist to announce a DualDisc release of his album was Sony/BMG recording artist Will Young.