Two new disc formats may finally deliver high-res digital audio—and end the CD, SACD, and DVD-Audio debateOctober 31st, 2008 -- by Robert Harley
More than twenty years after the CD’s introduction, we’re still listening primarily to 44.1kHz, 16-bit digital audio— and all its sonic limitations. Although two high-resolution formats, Super Audio CD and DVD-Audio, can offer significantly better sound than CD, both failed to become the standard for packaged music media. Mass-market acceptance of any format is crucial to audiophiles and music lovers because we want to buy all music in high-resolution, not just a limited number of titles from specialty labels. Unless a high-resolution format is sold at Wal-Mart, we’ll be limited in the number of titles we can enjoy in high-res.
With CD’s fundamental technology outdated and a single, universally available high-resolution music carrier out of the picture, where do we go from here? The answer is, unfortunately, a bit complicated. The good news is that two new disc formats on the horizon can deliver high-resolution digital audio. The bad news is that the music industry may simply ignore the potential of these new formats in the belief that the general public doesn’t care about sound quality. Complicating matters further are the facts that the two new disc formats are incompatible, and their backers are rushing headlong into a format war that may doom both discs.
The two new formats are HD DVD and Blu-ray Disc, both of which are vying to become the high-definition video replacement for DVD. HD DVD, supported primarily by Toshiba, has a capacity of 15GB per layer, with up to three layers per disc. HD DVD can deliver more than two hours of high-definition video accompanied by very highquality digital audio The competing Blu-ray Disc format, developed primarily by Sony, has even greater capacity: 25GB per layer, with up to four layers per disc. (Sony claims that an eight-layer version, with 200GB capacity, is working in the laboratory.)
Written into both formats’ specification is the provision for a musiconly disc. The HD DVD spec calls for up to eight channels of linear PCM digital audio with a sampling rate of up to 96kHz and a word length of up to 24 bits. Blu-ray can deliver up to eight channels of linear PCM digital audio at up to 192kHz and 24 bits. In essence, both discs offer DVD-Audioquality digital audio. There is an opportunity here for one of them to become the standard for music releases and replace CD, DVD-Audio, and SACD. Ideally, every title—catalogue and new release—would be issued in the new high-res format. Keep in mind, however, that even if HD DVD or Blu-ray does become the standard for music releases, it will take many years—perhaps a decade—before a large number of titles and goodsounding players becomes available. Until then, continue adding to and enjoying your CD, SACD, and DVDA music libraries.
It’s significant that the Sony-developed Blu-ray Disc incorporates linear PCM, not the Direct Stream Digital (DSD) encoding method it developed for SACD. Gaining widespread industry acceptance for Blu-ray as a highdefinition video carrier outweighed Sony’s desire to establish DSD as an audio standard. The recording industry’s technical infrastructure is based on PCM; trying to force DSD on the industry would have weakened support for Blu-ray.
HD DVD and Blu-ray would appear to be the music industry’s savior, offering them a secure new format that can’t be ripped or downloaded from the Internet, courtesy of highly advanced copy-protection technologies. Oddly, neither the HD DVD and Blu-ray hardware factions, nor the major record labels, appear interested in the music-only version of the discs. The hardware companies are concentrating on vastly more lucrative video applications. (Imagine the patent royalties that flow from creating DVD’s replacement.) And the music industry pursues further consolidation as the answer to its problems rather than delivering a better product.
There’s an important lesson to be learned from the bungled launch of DVD-Audio. That format was crippled from the start because its creators began selling DVD-Video players before the DVD-Audio specification was finalized. The hardware companies believed that only a few hundred thousand DVD-Aincompatible players would be sold before DVD-A could be added to second- generation machines. (“That’s the price paid by early adopters,” said an industry executive at the time.) But DVD-Video was an explosive hit, and by the time DVD-A-compatible players were released, the installed base of DVD-A-incompatible machines was in the tens of millions. (The debacle of the 17-year-old Norwegian kid breaking the decryption key and distributing it on the Internet further delayed DVDA.) The industry’s solution was to add a Dolby Digital track to DVD-A titles. Although this trick made the discs compatible with the earlier machines, it caused many consumers to believe that the highly compressed Dolby Digital track (about one-tenth the data rate of CD) was the high-resolution version.
The hardware and music industries should learn from these mistakes as they launch HD DVD and Blu-ray—if they introduce a music-only version at all. The next-generation music carrier cannot be an afterthought. Based on the hardware companies’ focus on the brass ring of replacing DVD-Video, and the music industry’s belief that consumers don’t care about sound quality, I’m not optimistic.
HD DVD and Blu-ray Disc
HD DVD was developed largely by Toshiba, and is supported by Sanyo and NEC on the hardware side, along with film studios Warner, Universal, and Paramount on the software side. Originally scheduled for launch in November 2005, the format was delayed until March of 2006, reportedly to give movie studios one more holiday selling season with DVD. The first player will sell for $999, and about 100 movie titles will be available at launch.
HD DVD is very much like DVD, but offers about triple the data capacity per layer by employing smaller information-carrying pits and a shorter wavelength playback laser. The format’s proponents argue that replicating HD DVD discs should cost no more than DVDs, and that production lines can be converted from DVD to HD DVD in 30 minutes.
By contrast, Blu-ray Disc, developed largely by Sony and supported by virtually every other consumer electronics company, along with film studios Columbia Tri-Star, MGM, and Disney, is a complete re-invention of the 5" optical disc. Its greater capacity (25GB per layer vs. HD DVD’s 15GB) is partially the result of even smaller pits and tighter track-spacing. Consequently, Blu-ray disc replication is more complex and expensive. Blu-ray, already available in Japan, is expected to become available in the U.S. next March. Both formats promise backward-compatibility with DVD. That is, the disc will contain a DVD layer that will play in legacy machines, as well as the HD layer compatible with the new players.
The competing sides tried and failed earlier this year to reach a joint format that would have avoided a format war. It would be a shame if these superior technologies fail in the marketplace because of consumer confusion or fear of buying into the “losing” format. RH
New Audio Formats for Concert Performances
Whether or not we get an audio-only version of HD DVD or Blu-ray, video concert performances are about to sound a whole lot better. DVD’s Dolby Digital, with its data rate of 384kbps (or 448kbps) will be replaced by the new Dolby Digital Plus format on HD DVD and Blu-ray. Dolby Digital Plus’ data rate of 3Mbps is more than six times that of Dolby Digital.
An extension of Dolby Digital Plus, called Dolby TrueHD, delivers high-resolution multichannel audio with perfect bit-forbit accuracy to the source with a data rate as high as 18Mbs. That means you will hear the same high-resolution multichannel datastream with movies and concert discs as was heard in the studio. Dolby TrueHD is an option to the disc’s producers; Dolby Digital Plus is mandatory. Incidentally, Dolby TrueHD is based on Meridian Lossless Packing (MLP), the lossless compression algorithm developed by Meridian Audio that was adopted for DVD-Audio. Dolby Labs was MLP’s licensing agent, and because it added new features to the core technology, it renamed it Dolby TrueHD.
Similarly, DTS encoding will be replaced by the higher datarate DTS-HD. DTS-HD has a scalable data rate all the way up to high-resolution multichannel audio with lossless coding. Dolby Digital Plus, Dolby TrueHD, and DTS-HD are backward- compatible with the tens of millions of existing decoders. HD DVD and Blu-ray players will have an SPDIF digital output that delivers a Dolby-Digital- or DTS-compatible signal. You won’t hear the benefits of the new formats, but at least you won’t have to buy a new controller or A/V receiver. (The Dolby- Digital-compatible signal will always run at 640kbps, which sounds slightly better than 448kbps, the upper limit of Dolby Digital on DVD. Conventional DTS runs at 1.5Mbps.)
The new players will also provide a high-resolution, multichannel digital output on an HDMI connector to connect with the next generation of controllers and receivers with HDMI inputs. It’s important to note that HD DVD and Blu-ray players will decode Dolby Digital Plus, Dolby TrueHD, and DTS-HD into high-resolution PCM for output to the controller or AVR. Because all modern controllers and AVRs operate on high-resolution digital signals (usually 96kHz/24-bit), no additional decoding is required in the controller or receiver. Finally, HD DVD and Blu-ray will output eight-channel, high-resolution analog signals on eight RCA jacks for connection to a controller or receiver’s multichannel analog inputs. (For a more detailed report on HD DVD and Blu-ray Disc, see Issue 60 of The Perfect Vision. For more on the new multichannel audio formats, see the Winter 2006 issue of TPV.)