Recently, there have been a number of exciting developments in digital versatile disc (DVD) technology. Just a year ago, recording to DVD was a big-budget affair. Today, however, DVD-Recordable (DVD-R) drives and media are hitting the streets at applications.
The benefits of using DVD technology in the personal studio are substantial. However, so that they can make intelligent decisions when mastering their music in this medium, it is important for musicians to learn about the various physical and application formats that come under the guise of DVD.
What are the differences between the various DVD formats? What can you do with a DVD that can't be done with CD? Let's take a look.
Part One: Dissecting DVD
Like CDs, DVDs originally entered the marketplace as a nonrecordable format. However, unlike the development of the CD-Recordable format, which occurred a number of years after CDs were introduced, the first DVD-Recordable drives and media appeared within a few months of the release of DVD. DVD-R was created in part to meet the demands of content producers who needed a reasonable way to proof their releases.
The first drive to hit the market, the Pioneer S-101, was priced at $17,000. Although the price was steep, DVD producers quickly found that they couldn't live without this tool.
Recordable DVD technology got a giant boost in 1999 with the release of the Pioneer S-201 ($5,400). At less than a third of the price of the S-101, the S-201 opened DVD-R to a broader market. At the same time, inexpensive yet incompatible DVD-RAM drives and media became available. In January 2001, Pioneer announced the release of the Pioneer A03, a so-called Super Drive that handles write-once and write-many DVD formats as well as CD-R and CD-RW. Pioneer believes that it will be able to price the A03 substantially less than $1,000.
Other manufacturers (notably Panasonic) have now entered the market, and Compaq and Apple are bundling DVD-R drives with their products. Component drives priced less than $1,000 for existing computers were expected to hit the stores in June. By the time you read this, recordable DVD will be a reality for mainstream consumers, with multiple offerings available from a growing list of vendors.
DVD has three primary uses: in desktop applications as a giant “bit bucket” for data storage; in consumer-player applications using the standard consumer DVD formats; and in hybrid applications that can combine standard DVD features with special functions, such as Web linking, that are available only when the DVD is played on a computer.
Standard and hybrid DVD applications offer five basic benefits over compact discs: DVD audio quality surpasses the audio quality of a normal CD; DVDs are able to store discrete, multichannel surround sound and high-quality video; DVDs offer much longer playing times than do CDs; and PC-based interactivity can be authored into a DVD. Although you can combine these features, there are limits to the ways that video images, high-density audio, and surround sound can be used together. For example, with the DVD-Video format, multichannel surround audio is only available in a data-compressed form when it accompanies video content. If you want your audio uncompressed, you are permitted only two channels.
A BALL OF CONFUSION
You will need a little more than the usual knowledge and ingenuity to tap the DVD-R's full potential while staying within your budget. To begin with, there are a number of different formats to work with, and there are incompatible variants within the most prevalent format as well. Incompatibilities linger between the recordable media and some players on the market, which affects the range of practical applications.
In addition, there are multiple DVD applications for musicians to consider. The great majority of players play the DVD-Video format only. However, DVD-Audio offers important advantages for musicians (see the table “DVD-Video and DVD-Audio Capabilities”).
Finally, although there are a number of affordable tools for preparing and mastering DVD-compatible content, such products tend to be biased toward video and often do not support the full range of DVD's audio capabilities. To use the current crop of DVD authoring tools solely for audio applications requires special knowledge and careful attention. Depending on your requirements, the costs of the tools can vary greatly.
RECORDABLE OR REPLICATED
In order for DVD to become a commercially viable format, two technological hurdles needed to be overcome. Disc manufacturers needed to be able to consistently meet the necessary tolerances in pit size and track pitch (which is the distance from one data track to another) in order to put several times more data on a DVD than they were able to put on a CD. The second requirement was a laser element that could read those much finer pits. The size of the pit that can be read by an optical drive (CD or DVD) depends on the wavelength (or color) of the light emitted by the pickup head. The lasers required for DVD, which read shorter wavelengths, became available in the late 1990s.
For both CDs and DVDs, there are fundamental differences between a manufactured disc and the recordable medium. Up to this point, I've been referring to pits on the disc. In reality, the data on an optical disc can be represented in several ways. The player's laser-pickup head includes a light-emitting laser diode and a separate photo diode that responds to light and dark. The laser diode focuses its beam of light at the target. The photo diode sees the return signal as either light or dark. In manufactured CDs and DVDs, data is represented by pits that scatter the light or lands that reflect it straight back to the pickup head.
In recordable DVD and CD technology, there are no pits. Light and dark states are produced by a photosensitive dye or a metal alloy, the reflectiveness of which changes in response to the writing laser.
Because DVD players are designed principally to play commercially mass-produced discs, there is no guarantee that the laser pickups on a given player will match the reflective characteristics of today's DVD-R discs. That is especially true with older DVD players.
Replicated DVDs also have a technology element not present in CD: the ability to put data on separate layers. Both data layers of a DVD disc are transparent, and both have a reflective layer behind them. The drive's laser-pickup head focuses on one layer or the other. That ability is similar to the way you can look out a window on a rainy day and selectively focus on the raindrops or on the landscape beyond. However, with DVD-R, in which the medium is opaque by nature, there is only a single layer.
RECORDABLE DVD FORMATS
One confusing factor for the novice is the variety of recordable DVD formats. Each format has its own features and is promoted by a different group of manufacturers. Although the dust hasn't completely settled on the issue, a few things can be said about the state of the technology and the market today.
DVD-R (the original). Sometimes referred to as DVD minus R, DVD-R is the most prevalent form of recordable DVD today. DVD-R drives have been on the market since 1997, and generally the technology has maintained a record of good compatibility and stability.
But just to keep matters confusing, DVD-R has now split into two separate trunks: DVD-R Authoring and DVD-R General. Technologically, the difference between the two is in the wavelength of the laser used. Economically, the difference is in the cost of the players and the blank media.
DVD-R drives and media sold prior to 2001 are now considered to be in the Authoring category. Authoring items are for use primarily in professional applications. Expect to pay about $4,000 for a professional-quality recorder and about $20 per blank disc.
Blank DVD-R Authoring media come in two sizes: 3.95G and 4.7G. (For an explanation of the difference between the disc-size indications G and GB, see the sidebar “DVD Capacity and Nomenclature.”) The 3.95G discs, which hold slightly less data than standard replicated 4.7G DVDs, were first to hit the market. Of all recordable DVD forms, 3.95G discs have the best compatibility with existing consumer players.
DVD-R Authoring provides a means to create a replication master in the Cutting Master Format (CMF) that can be used directly for disc manufacturing. In addition, the DVD-R Authoring format is free of restrictions on copying that apply to the lower-priced General format.
The DVD-R medium most likely to be used by desktop musicians is known as DVD-R General. Blank DVD-R General discs come in only one size, 4.7G. The format employs a different laser wavelength — 650 nanometers — than DVD-R Authoring, which means that DVD-R General drives cannot read or write to DVD-R Authoring media and vice versa (see Fig. 1).
DVD-R General is aimed explicitly at consumer-level users, so the drives and blank media are much less expensive than those for the Authoring format. That should lead to the widespread adoption of the General format for many kinds of applications.
The bad news is that a few specific functions are restricted with DVD-R General. Unlike the Authoring media, for instance, General media cannot be used as a direct replication master using CMF.
DVD-R General also includes ingenious measures aimed at preventing content piracy. Digital data scrambling in commercial discs prevents direct file copying, and DVD-R General discs also blank out specific areas of the disc that normally carry the decryption keys. The copy protection provisions in commercial DVD titles are intended to prevent analog recording of DVD-based video to tape. Although those provisions are unlikely to deter professional pirates, they should be effective in keeping casual duplication to a minimum.
According to manufacturer's white papers, both forms of DVD-R are fully compatible with consumer players; however, real-world experience belies that claim. The compatibility may be good, but it is clearly not perfect. For that reason, general distribution of productions on DVD-R won't be practical until the population of older, problematic players gets flushed out or reduced to a much smaller percentage of the installed user base.
You will encounter the smallest number of compatibility problems if you use the 3.95G version of DVD-R Authoring media. Though Authoring discs are a lot more expensive than blank General discs, you don't want to take a chance that your disc won't play when you hand over your demo to someone important. Therefore, establish a connection with a suitably equipped service bureau that can copy important projects to the Authoring format. In my experience, I have found it makes a difference.
DVD-RW. DVD-RW uses a different principle for recording than DVD-R, one that is inherently erasable and rewritable. Whereas DVD-R uses a dye that changes color, DVD-RW uses a metal alloy (of silver, indium, antimony, and tellurium, in case you were wondering) as the writing medium (see Fig. 2). That alloy can change back and forth many times between reflective (crystalline) and nonreflective (amorphous) states. The stated life of a DVD-RW disc is in excess of 1,000 write/erase cycles.
DVD-RW has compatibility issues similar to those of the other forms of recordable DVD. Most players can play a DVD-RW, but if you don't know the player type and its compatibility with the media ahead of time, you can't be sure the disc will play.
Remarkably, the behavior of a player with a DVD-R disc does not predict its behavior with a DVD-RW disc or vice versa. If a DVD-R disc fails to play, it's generally because of difficulties with the reflectiveness at a given wavelength. The metallic write layer of DVD-RW has plenty of reflectiveness across a broad range of wavelengths, but the reflective characteristic matches what the DVD spec defines for the second layer of a dual-layer disc (also known as a DVD-9 disc). The firmware of some players sees that characteristic and assumes it should change focus to see deeper into the disc than it actually should. According to the manufacturers, the issue for a given player can be fixed by a firmware update.
Most DVD-R General drives also support DVD-RW, but blank DVD-RW discs are considerably more expensive. A good strategy might be for you to have a very small number of DVD-RWs to use as scratch discs and to use more affordable write-once DVD-R media for anything you want to give out or keep for an extended time.
DVD+RW. Just to make life even more interesting, a group of companies (including Sony, Hewlett-Packard, and Phillips) is pushing an alternative read/write format that is incompatible with both DVD-R and DVD-RW. The format is called DVD+RW (pronounced DVD plus RW, with the implication that the other format is somehow DVD minus RW).
The availability of DVD+RW drives and media is lagging behind that of DVD-R. However, the DVD+RW Alliance has announced a full rollout of DVD+RW products during the summer of 2001. By the time you read this, DVD+RW may be much more widely available than it is at the time of this writing.
The DVD+RW Alliance claims that DVD+RW is more compatible with existing players than is DVD-RW and that the medium is better suited for real-time video recording and editing applications. That remains to be seen. Until real-world field experience with DVD+RW can be obtained, it's impossible to assess the relative merit of the format over DVD-RW.
DVD-RAM. The remaining competing format, DVD-RAM, has been available for years, is fully rewritable, and costs even less than DVD-R. The problem for DVD-RAM is opposite that of DVD+RW: it has essentially no compatibility with commercially available consumer players. For most purposes, DVD-RAM disks can be used only in computers with DVD-RAM drives.
However, DVD-RAM's proponents — notably Panasonic and Hitachi — are continuing to develop the format and have shown conceptual prototypes of a number of consumer appliances, such as video recorders, based on the format. In a nod to the way things are shaping up, though, Panasonic's new LF-D311 Combo Drive will record and play DVD-R and DVD-RW as well as DVD-RAM.
CHOOSE YOUR FORMAT
If you find all of this a bit confusing, you are not alone. Ultimately, market realities will help you narrow down your format choices.
Unless the DVD+RW format comes on strong during the middle of 2001, DVD-R and DVD-RW will be the de facto winners. Those formats have a strong installed base of drives and media that are compatible with the majority of DVD players in the field. Some share of those players will also be DVD-RAM compatible, which may give an edge to that format in certain applications. But my bet is that from here on out, the term recordable DVD will be synonymous with DVD-R and DVD-RW.
Still, the compatibility issues between recordable DVDs and consumer-level DVD players persist. Unfortunately, none of the manufacturers will admit that their products have those problems, so acquiring useful, objective information is difficult. To see the best publicly available compatibility listing for DVD-R General, visit Apple's Web site on DVD compatibility (www.apple.com/dvd/compatibility). The list is by no means complete, but it is updated on a regular basis as new products are tested.
Eventually, problems with player compatibility will go away. Newer players are generally fully compatible with DVD-R and DVD-RW, and the majority of consumers still have not bought their first DVD player. Therefore, we can expect the number of incompatible players to diminish.
FILE SYSTEMS AND ACCESS
Physically, an optical disc is nothing more than a platter covered with pits and dots (or light and dark areas in recordable media) arranged into a very long spiral track, with redundancy codes and marks that allow the stream to be converted reliably into a string of digital bytes. Before anything very useful can be done with an optical disc, a means of locating the information stored on it is needed. The DVD specification provides more than one way for a reading device to retrieve information from a disc.
When the compact disc came into being, it was conceived as an audio playback medium, so a simple addressing scheme was developed: from the head of the disc, a CD player reads a table of contents, which identifies the location of tracks and indexes based on a sector offset. That addressing system gives the CD player its random-access capabilities.
When CD technology was first used with computer applications, developers found that there was no specification for arranging files hierarchically. The result was that for a long time the CD-ROM format had compatibility problems from one computer to another.
Eventually the computer industry created a standardized file system called ISO-9660. The ISO-9660 standard has certain limitations, for example, short file names and a limited ability to nest folders. Nevertheless, the standard allowed CD-ROMs to flourish as a common format.
In formulating the DVD specification, DVD Forum members were careful not to make the same mistakes. For example, CDs were originally designed as a consumer format. Later, developers had to graft the computer elements onto the consumer format to make CD-ROMs. The DVD Forum also recognized that the sector offset scheme employed in CD audio is frequently more suitable for low-cost consumer players because it doesn't take as much memory and processing power to execute.
DVD makers wanted to agree on a file system early in the game. As a result, the DVD specification mandates that every disc will include two complete file systems. One is a new, far more sophisticated file system called Universal Disc Format (UDF) that overcomes many of the limitations of ISO-9660 while making the management of rewritable media much more straightforward. However, no computer at the time the DVD spec was formalized had UDF implemented, so it was necessary to include ISO-9660 as an alternative file system. The particular model of DVD player you have will determine which access scheme is used.
One powerful advantage of the standardized file system is that every DVD disc is inherently readable by computer, without any special preparation or software needed. That makes it easier to incorporate computer-specific enhancements into a DVD title, including bonus elements such as screen savers, wallpaper, games, and Web connections. Such enhancements have become a popular way to add value to commercial DVD titles.
The application layer is the specific arrangement of a set of files on a disc. For example, the definition of the DVD-Video application layer includes the kinds of media content that can be played, the options that are available, and the means of describing the intended relationships. That framework allows content creators to take advantage of the format's interactive possibilities, such as multiple audio streams, menu-based navigation, and switchable subtitles, with full assurance that the results will be compatible with any DVD player.
The specification of the physical format and file systems consumes approximately 100 pages of the DVD spec. Defining what goes into an application layer such as DVD-Video takes an additional 500 pages.
The definitions in the application layer appear on the disc as a specific set of files arranged inside a directory with a fixed name, such as Video_ts on a DVD-Video disc (see Fig. 3). You can look at the directory by putting the disc into a DVD-ROM-equipped computer and using the computer's browser to examine the file structure. Inside the Video_ts directory, different files are designated as media content (VOB files, which contain video, audio, and overlay information multiplexed together in a tightly defined pattern) and navigation (IFO) files. The navigation files consist of a set of tables and pointers that tell the player everything it needs to know about the content and how the author wants it to play. Every IFO file is accompanied by a backup (BUP) file.
A DVD's directory can be stored on hard disk or other media besides DVD. A subculture of DVD applications involving DVD-Video-format content stored on CD has already sprung up. Such discs are incompatible with the great majority of DVD players, but they play well on computers. That Mini-DVD format (which is not a standard, by the way) is not very useful for music, however, because computer-based DVD players do not tend to support high-density audio and are rarely connected to surround-sound playback systems.
DVD-VIDEO VS. DVD-AUDIO
Two different application layers exist that apply to the needs of musicians. What most people think of as DVD is DVD-Video. But another format, DVD-Audio, is specifically tailored to the interests and needs of audiophiles and music producers.
Although the DVD-Audio specification is attractive, the format is far less established in the marketplace than DVD-Video, and tools for producing DVD-Audio content are harder to find and more expensive. That set of circumstances could potentially change, but currently, producing DVD-Audio content is out of the price range of most musicians.
Tools for creating DVD-Video content, on the other hand, are readily available at a wide range of price points. It therefore makes sense to focus on the application of DVD-Video for music while monitoring the development of DVD-Audio. Even if DVD-Audio continues to develop slowly in the consumer world, a set of simple, low-priced authoring tools would make it a useful format for content development.
DVD-Video gives you 2-channel audio at 24-bit, 96 kHz resolution, as well as discrete surround channels (albeit compressed in Dolby AC-3 or DTS format). The DVD-Video standard stipulates that all DVD players must be able to play audio streams in Dolby AC-3 format with as many as 5.1 (three front, two rear, and one subwoofer) channels. The specification also provides for the use of audio compressed in the DTS format. Many consider DTS a higher-fidelity alternative, though player compatibility is not mandated by the DVD specification. To make use of DTS in a DVD title intended for the open market, it's necessary to include an alternate version in Dolby AC-3 or pulse-code modulation (PCM) stereo format.
A carefully compressed surround track in Dolby AC-3 or DTS can sound stunning and can be reproduced by commercially available home-theater systems. Compressed audio, however, is certainly not acceptable for archival or production. For those purposes, data can be placed as raw files in the ROM area of the disc, where any computer with a DVD-ROM drive can access it.
Although DVD-Video supports purely audio applications quite nicely, musicians must take into account the format's requirements. In particular, the DVD-Video spec requires that some sort of picture be present in order to play audio at all. To produce pure audio titles in the DVD-Video format and satisfy that requirement, DVD-Video authors place a single still image in the video track. The image can be black or a simple listing of the title. Not all DVD-Video production tools support the use of still images, so that is a feature to look for when you select DVD authoring software.
An additional application layer definition is aimed at consumer video recording and editing applications using the three rewritable formats (DVD-RAM, DVD-RW, and DVD+RW). The Video Recording format (DVD-VR) specification allows for random-access assembly editing and for trimming of video and audio segments.
Pioneer and Panasonic have shown DVD-based consumer video editor/recorders using the recordable format favored by each (DVD-R and DVD-RAM, respectively). The devices are ingenious in their operation and capabilities, but whether they strike a chord with the buying public remains to be seen.
It is not clear at this point whether the audio capabilities of DVD-VR devices will be of interest to musicians, but it is a possibility. The next generation of portable audio workstations could certainly be based on some form of recordable DVD rather than depending on hard disk or MiniDisc.
PRO DVD-R DRIVES
The field of recordable DVD products is in considerable flux; affordable drives and media are just beginning to hit the market. The following describes the products available for summer 2001.
Pioneer DVD-S201. At $5,400, Pioneer's S201 (now venerable after almost two years on the market) may not be affordable for most EM readers, but there's no doubt that it's the standard for professional DVD production. It supports DVD-R Authoring media in both 3.95G and 4.7G formats as well as CMF for mastering directly from DVD-R. The drive is produced exclusively as a standalone unit with its own power supply and SCSI interface.
Although economics may dictate the use of DVD-R General products for most personal-studio musicians, there are many service bureaus that offer services using the S-201. It's a good idea to use such a bureau for the occasions when you need to burn a 3.95G disc for its superior player compatibility or to produce a CMF replication master.
Pioneer DVR-103 and DVR-A03. Pioneer currently produces the leading presence in DVD-R General drives: the DVR-103 and DVR-A03 (see Fig. 4). Those units, which are otherwise identical, are packaged for OEM and aftermarket, respectively.
Sometimes referred to as Super Drives (particularly by Apple), the DVR-103 and DVR-A03 drives record DVD-R and DVD-RW as well as CD-R and CD-RW. As players, they support all forms of replicated DVD and CD including CD-R, CD-RW, DVD-R, and DVD-RW. The drives do not support competing recordable DVD formats such as DVD-RAM and DVD+RW, however.
Both drives use the ATAPI interface, which might complicate the process of adding either drive to existing, heavily SCSI-based systems. Currently, the DVR-103 is shipping in limited quantities in computer bundles from Compaq and Apple, but at an estimated street price of less than $900, the standalone DVR-A03 is setting the pace for price and performance in recordable DVD.
Panasonic LF-D311 Combo Drive. Not to be outdone, Panasonic has announced that its LF-D311, a combination DVD-R and DVD-RAM (but not CD-R) drive, would be available in the early part of the summer. The company indicated that prices would be comparable to those of the Pioneer units.
Also using the ATAPI interface, the Panasonic drive is likely to be a strong contender in OEM and aftermarket configurations. The drive will be of interest to those who would like to use the lower-cost reusable DVD-RAM media during title development but who still want to be able to deliver a write-once player-compatible DVD-R to clients or replicators.
DVD-R General drives are available only in bundled configurations. Here's a quick look at the two systems that are on the market.
Compaq Presario 7000. The current top end of Compaq's range, the Presario 7000, is available in a wide range of configurations. One option is the inclusion of the Pioneer DVR-103 drive (see Fig. 5). A representative configuration (1.2 GHz Athlon processor, 384 MB DRAM, and 40 GB hard drive, but no monitor) with DVD-R lists at $2,445 on Compaq's Web site.
Apple Power Mac G4. The G4 (see Fig. 6) is available with the Super Drive in a standard configuration at a price of $3,499. That setup includes a 733 MHz processor, 256 MB DRAM, and a 60 GB hard disk (without monitor).
Both systems come bundled with entry-level DVD-authoring software. Compaq includes Sonic Solutions DVDIt; Apple includes its own program, iDVD. For musicians, there's a good chance that the bundled software won't meet the needs of production, because those products tend to support only a small subset of DVD-Video's audio capabilities.
CONSUMER DVD RECORDERS
To date, both Pioneer and Panasonic have introduced standalone recorders for consumer use. In their current iterations, the DVD-R-based DVR-1000 ($2,035) from Pioneer and the DVD-RAM-based DMR-10 ($3,995) from Panasonic are focused entirely on home-video applications and support only two channels of data-compressed audio. Both units include capabilities for trimming and sequencing clips, similar to those on MiniDisc devices. However, discs recorded on either DVD recorder will not play on standard DVD-Video players.
Those particular commercial units may not be of immediate interest to musicians, but the possibility certainly exists that more sophisticated recording and production devices based on recordable DVD technology could become available in the near future. For example, application standards for DVD Audio Recording (DVD-AR) and DVD Stream Recording (DVD-SR), analogous to the DVD-VR standard on which these products are based, are currently being developed.
In the coming months, you can expect the pace of technological development and product introductions to accelerate. DVD recordable drives will become increasingly prevalent, and more computer bundles and aftermarket add-on drives will become available.
I expect that, eventually, recordable DVD will replace CD-R and CD-RW in terms of affordability and market prevalence. Furthermore, standalone DVD-based recorders for video and audio will become more common. Surprises are still possible, but based on current trends, it seems that the majority of the drives installed in computers will be based on DVD-R and DVD-RW technology in combination with CD-R, CD-RW, DVD-RAM, or DVD+RW formats.
Part Two: Diy DVD
No matter which recordable DVD formats become standard, musicians will want to use DVD for delivering music, video, and interactive content. In this section, I will examine the production processes and the hardware and software needed to create discs compatible with standard consumer DVD players.
DVD-AUDIO VS. DVD-VIDEO
Of the two consumer-oriented DVD formats, DVD-Video has caught on most quickly. DVD-Video has been as aggressively developed for distributing movies as the compact disc was for music. Standards were worked out early, compatible players have been manufactured in huge quantities, and many thousands of titles are available.
Whereas DVD-Video provides a rich set of features for movies and interactive entertainment, DVD-Audio focuses almost entirely on high-fidelity and advanced multichannel sound.
Because the specification took so long to solidify, DVD-Audio is just now entering the market. Factors that delayed the release for more than a year include intellectual-property rights protection and copyright infringement — the debate over DeCSS, which can be used to crack DVD copy protection, for example.
Until recently, most consumer players couldn't play DVD-Audio. Now, there are players available that play both DVD-Audio and DVD-Video. More players on the market will now have dual-format capability, so the population of compatible players will increase dramatically with time. Only a few dozen DVD-Audio titles are available, but the major labels that support DVD-Audio (Warner Brothers, primarily) promise to make a large body of titles available at the beginning of the 2001 holiday season.
With sampling rates as high as 192 kHz and digital word lengths to 24 bits, DVD-Audio offers the highest resolution available in a commercial digital-audio playback medium. That means that the information density of DVD-Audio is greater than that of CD by a factor of nearly 800, and DVD-Audio has double the highest audio density available in the DVD-Video format.
In terms of multichannel surround sound, DVD-Audio gives you six channels of uncompressed high-resolution PCM sound. On the other hand, delivering multichannel surround sound on a DVD-Video requires Dolby AC-3 or DTS data compression, which have lower audio fidelity.
DVD-Audio lets you use still pictures to accompany audio tracks. When connected to a video screen, DVD-Audio can display as many still pictures as desired, and you can switch from picture to picture without interrupting the audio track. DVD-Video also provides still images, but pictures are locked to sound and cannot be advanced without disrupting playback.
Most commercial DVD-Audio releases include at least one music video. The video is played from a DVD-Video area on the disc, so the audio specs accordingly decrease to those of DVD-Video. If your projects are based on audio accompanying video, DVD-Audio offers no fidelity advantage.
A single disc can include separate DVD-Video and DVD-Audio programs. Because the player population currently is disproportionately slanted toward DVD-Video players, nearly all commercial DVD-Audio releases are dual-format. Both formats have essentially the same program material, but with reduced audio specifications for the DVD-Video portion.
Because DVD-Audio has been slow to emerge as a consumer product, the state of the authoring software is about where it was for DVD-Video three to four years ago. Few programs are available for DVD-Audio, and they are expensive. The least expensive authoring package sells for $6,000 and doesn't cover all features in the medium. A full production system capable of authoring commercial DVD-Audio titles will cost in the low tens of thousands. Authoring tools for DVD-Video are available for a range of prices and include affordable offerings that support most, if not all, of DVD-Video's advanced audio capabilities.
Eventually, the price of DVD-Audio authoring tools will decrease. For now, musicians without major resources who want to take advantage of consumer DVD's capabilities will have to work in the DVD-Video format. That is not necessarily a bad thing: DVD-Video offers many of the capabilities of DVD-Audio as well as more options for interactivity and combining music with visuals.
I will now focus on the tools and techniques needed to take advantage of DVD-Video's audio, video, and interactive features with regard to musical applications.
AUDIO ON DVD-VIDEO
As mentioned previously, audio material can be put on a DVD-R in the DVD-Video format using readily available and reasonably priced software. Because DVD-Video was designed with video in mind, it has some special considerations.
Remember that the DVD-Video spec doesn't allow you to put audio on a DVD-Video disc without some kind of video track or still image. If your work is not video oriented, you can fulfill the requirement by placing a single still picture at the head of each audio track. You can also use a succession of stills to form a slide show to accompany your music.
Unfortunately, some of the DVD-Video authoring programs, especially inexpensive and bundled software packages, do not support the use of still pictures. When choosing a DVD-Video authoring program, be sure your selection will let you use stills in place of video.
DVD-Video lets you make as many as eight different audio programs available. The viewer can switch between audio streams, using the DVD remote control. For movie titles, the various audio programs commonly contain foreign language tracks, commentary, and alternate mixes for stereo and surround. Karaoke titles often use the alternate audio streams to provide versions with and without vocals and guide melodies.
Lower-priced DVD authoring packages may only support basic capabilities for data-compressed stereo. The audio options you want supported on your DVD may determine how much you will need to spend on an authoring package.
SOUND AND COMPRESSION
Data compression preserves disc space. For video content on commercial DVDs, the accompanying 2-channel audio is commonly compressed in the Dolby AC-3 format. However, producers may not want to use data-compressed audio unless they need longer playing time. Fifty-four hours of continuous stereo audio material can be put on a 4.7G DVD-R disc using AC-3 compression.
The question of choosing a data compression format for stereo sound in DVD-Video involves an interesting twist. The DVD-Video specification lists MPEG-1 Layer 2 audio (a sibling of MP3) as an option for DVD-Video, but it requires that a track be in Dolby AC-3 unless uncompressed PCM audio is used. MPEG-1 audio is effectively free, but Dolby collects a royalty on every AC-3 encoder and decoder in the field. For manufacturers and musicians looking to save money, the incentive is to try to get by with MPEG-1 Layer 2 compression. Unfortunately, the manufacturers of DVD players have interpreted the specs differently. Most American DVD players will play MPEG-1 Layer 2 audio. Note that MP3 is not a part of the DVD spec, although a few DVD players can play MP3s from CD or DVD.
HIGH-DENSITY PCM STEREO
Sampling rates for PCM audio on DVD can be either 48 or 96 kHz, with a bit resolution of either 16 or 24 bits. For stereo PCM audio, the only advantage that DVD-Audio has over DVD-Video is the support of 176.4 or 192 kHz sampling rates. To date, however, those rates have been used little even in DVD-Audio releases.
High-density PCM audio is bandwidth-hungry, and commercial DVD-Video titles generally use it only if audio is an important aspect of the program, as it would be in a concert video. The data-transfer rate for DVD is constrained to a total of 9.8 million bits per second (mbps) for audio and video combined. A program with 24-bit audio at a sampling rate of 96 kHz consumes more than 4.6 mbps, leaving a marginal amount of bandwidth for video and alternate audio streams.
DVD-Video does not support the CD sampling rate of 44.1 kHz. If you have occasion to transfer audio from CD to DVD, you need to convert the sampling rate of the audio before you can move it to DVD-Video. DVD-Audio, on the other hand, supports 44.1 kHz and its multiples, 88.2 and 176.4 kHz.
Lower-cost DVD authoring software may or may not support higher densities of PCM audio, and unfortunately, that information is not always evident from a manufacturer's data sheets. If you plan to make use of DVD-Video's capacities for ultrahigh fidelity, check that the authoring software you select lets you import and use high-sampling-rate and high-resolution PCM audio.
DOLBY AC-3 AND DTS
If you always wanted your music to be heard in multiple channels, now's your chance. Multichannel surround may be the coolest aspect of DVD for musicians, and DVD-Video is the format that has turned discrete multichannel playback capability from an exotic thrill to a viable release format for music.
In DVD-Video, multichannel surround audio (5.1 or 6.1) must be data-compressed into Dolby AC-3 or DTS formats. Data compression reduces the bandwidth and file size required for multichannel audio, allowing video and surround audio content to fit in the same program. Every DVD player will play tracks in Dolby AC-3, but only the minority can play back DTS. In addition, encoding and authoring tools for AC-3 are much more common and affordable than the products that support DTS.
If you are going to do multichannel surround work on DVD and you're not going to wait for friendlier DVD-Audio software prices, you will need a way to encode multichannel audio into AC-3 format. You will also need decoding capability for monitoring.
Many titles that use discrete surround audio have a stereo version of the same material for playback on systems not set up for multichannel surround. AC-3 provides for automatic mixdown of its five full-bandwidth channels into one stereo pair, but often results are not optimal.
Numerous musicians and producers prefer the sound of DTS compression. DTS uses higher bit rates for the same number of channels, which enhances fidelity. Because DTS not a format that players are required to support, titles that have a DTS surround track usually also carry an AC-3 version of the same material. Alternate stereo PCM tracks are included in many cases.
Unfortunately, most low-cost DVD authoring packages do not support DTS audio. You may have to go to the expensive professional packages to get full DTS capability for DVD-Video.
If you plan to create multichannel surround content in AC-3 or DTS, familiarize yourself with your tools, encoding's effect on sound quality, and the options and settings of your encoding software or hardware. Pay attention to levels and to bit rates. Data-compressed audio can sound really good — if you work at it.
Here's an AC-3 tip: for any given configuration, select the next higher bit rate from the one Dolby recommends. If you are doing 5.1, Dolby recommends 384 thousand bits per second (kbps), but comparative listening will convince you that 448 kbps (the next higher rate) sounds better in the higher frequencies.
Another feature to look for in a DVD authoring package is monitoring capability for discrete surround sound. Few of the available packages that include hardware and software can directly decode AC-3 5.1 or DTS audio to multiple channels. Most systems that use hardware for decoding and video monitoring are able to output AC-3 as an S/PDIF bit stream that can be decoded externally. DTS output capability is less common. In either case, an external decoder, such as a consumer receiver with Dolby and DTS capability, is required.
If you want to release multichannel surround titles but don't care about using DVD's other visual and interactive features, another option that can save you money is available. You can encode audio into DTS and burn it in CD-Audio format. The resulting discs play superbly on DTS-capable DVD systems and on CD players connected digitally to a DTS decoder. If you have a CD burner and multichannel content, the only additional tool required is a DTS software encoder.
Besides its advanced audio capabilities, DVD-Video offers cool features for interactive entertainment. Whether you are involved with visual production or not, the picture capabilities of DVD-Video may be an avenue for collaboration and a way to finance your gear and software with commercial video work.
DVD also provides an option for multiple parallel video streams called camera angles (the alternate streams can be anything you like, not just different views of the same thing). Viewers can select the streams or incorporate an interactive program to select for them.
For example, once play begins, you can have your title randomly select one of the DVD's eight alternate audio versions of a music piece and one of nine alternate video or computer graphic realizations to accompany it. That yields 72 ways a listener might experience a single piece.
In addition, DVD-Video can put simple graphic images on the screen over video or stills; as many as 32 alternate graphic streams can be available to the viewer. In commercial DVD titles, that overlay capability is used mostly for subtitles, but the same mechanism can be used for other, more artistic, purposes. DVD-Video authoring programs vary widely in how they support DVD subtitling. If you are interested in more elaborate and creative uses, be sure to check the features available when shopping for your authoring package.
DVD-Video uses graphic menu screens for navigation, and navigation schemes can be arbitrarily complex. DVD menu screens can consist of video or animation (with or without audio). Screens can also connect by way of animated transition sequences.
DVD-Video lets you put graphic navigation buttons on the screen as the main content plays, not just in a dedicated navigation menu. That can be an excellent way to let viewers jump from track to track at any time. However, not all of the affordable DVD authoring software packages support that function.
In addition, DVD-Video offers a fairly elaborate programming environment for interactivity complete with mathematical functions (including random number generation) and data storage. Viewers can peruse games and quizzes in which they answer a series of questions. Responses can be stored and used to generate a composite score or to control the next action of play. Playback can also branch based on random numbers or even the age of the viewer (using parental management features) to present different viewing experiences to different individuals. By and large, those capabilities are not available in DVD-Audio.
Everything, Everything by Underworld is a good example of what can be done in the DVD-Video format. The concert disc includes audio streams in 5.1 AC-3 and AC-3 stereo, both of which sound quite good. Spoken portions are provided in English, Gaelic, and Japanese.
The viewer has the option of selecting the concert footage or abstract video art on an alternate video angle. The viewer can select individual cuts for play or can define a specific order for the songs. On computer, a Macromedia Director presentation offers Web connections and more ways for viewers to interact with sound and picture.
For playback on a DVD-ROM-equipped computer, some interesting possibilities exist for combining DVD-Video content with computer-based material. By playing a DVD on a computer, for example, particular scenes and viewer actions can link your browser to corresponding Web sites. That type of interaction can be used to engage viewers more deeply or simply to involve them in online exchanges such as chats or product purchases.
Web-linked DVD has been such an intriguing idea commercially that the largest makers of DVD-Video authoring software incorporate some form of Web-linking capability in their applications, even at the low end. In most cases, creating a Web link entails entering a URL associated with a menu button or index (also called chapter or scene in DVD-Video) during the authoring process.
The cost to incorporate Web-linking into DVD projects depends on how elaborate you want to get. Even many inexpensive DVD authoring programs provide simple ways to link index points and menu buttons to specific Web addresses. But if you want to create refined Web-linked multimedia experiences, you may need more advanced software tools that allow DVD-playback windows and browser windows to fit together as orderly frames in a customer skin.
Web-linked DVD also has compatibility issues because of manufacturer implementation and the myriad configuration possibilities of users' PCs. Web-linked DVD can work for you, but expect a residue of playback problems to accompany any implementation.
Now that I've addressed the possibilities of the DVD-Video format, I'll discuss how they're implemented. Fig. 7 illustrates the process of DVD-Video production and the specialized tools that it requires. The process is essentially the same for DVD-Audio.
Consumer DVD (both DVD-Video and DVD-Audio) is a complicated reproduction medium. To provide all of the available features in a form universally compatible with consumer players, the DVD spec defines specific requirements for media data formats and control structures; it spells out in lavish detail how to weave multielement media streams and fully programmable, interactive random-access control into several billion bytes of intricately interleaved media information and elaborate tables of control information. (The sidebar “DVD References” lists resources with the most complete information available on the DVD spec.)
In this section, I will focus on using the DVD medium to publish content already in existence. I will assume that you already have the means to produce audio content in high-density stereo or multichannel surround form to take advantage of DVD's capabilities, as well as any video content required.
Although the majority of audio and video content is generally created prior to DVD authoring, certain common graphic elements are needed specifically for DVD. Those may be as simple as the single still graphic used to accompany audio in the DVD-Video format, but they often include any number of navigation menus and still images.
Still graphics for DVD menus are commonly created using standard graphics programs such as Adobe Photoshop. Menu graphics for DVD consist of a background image and a graphic overlay with button selections indicated by highlighted colors.
Generally, graphics can be provided in nearly any still-picture file format, but the picture dimensions are constrained to 720 by 480 pixels for NTSC (North America and Japan) and 720 by 576 for PAL (the rest of the world). JPEGs from digital cameras and so forth can be included easily but must be scaled to those dimensions before being imported into the authoring applications.
DVD-Video can also include animated menus as well as transition sequences. Those short visual sequences can be created using nonlinear editors and animation programs such as Adobe's Premiere and After Effects. Video, however, must be captured to MPEG-2 before being imported into a DVD project.
CAPTURE AND ENCODING
With the exception of uncompressed PCM audio, all of the audio and video data formats for DVD are data compressed in one of a number of standards. Video for DVD is always compressed with MPEG-2, following specific guidelines on bit rate and picture scaling.
Encoding video may be of little concern to you, but it deserves attention. Commercially, MPEG-2 video encoding is often done using real-time hardware, usually in the form of a single-slot PCI card. High-quality hardware-based video encoders can be expensive. Fortunately, many affordable DVD-Video authoring packages include software-based MPEG-2 encoders suitable for creative and informal use. Although slower than hardware-based encoding, those programs can create loops for motion menus and other short connecting material, as well as for encoding primary video content (if you're willing to wait).
To review, multichannel audio for DVD-Video must be compressed using Dolby AC-3 or DTS. Compressing stereo audio content is optional.
Although audio is presented at full resolution in the DVD-Audio format, there is a provision for a form of lossless compression called Meridian Lossless Packing (MLP). Software encoders are available for MLP, but the prices are proportional to the high cost of DVD-Audio authoring software and, as such, are generally not within personal-studio budgets.
ELEMENTS OF AUTHORING
Authoring software for DVD must provide a structure for combining elements that work for DVD, and ways to view the results before they are committed to disc. That is done through DVD simulation or emulation. The authoring software must also be able to multiplex several gigabytes of multiple audio, video, and graphic streams, and create the elaborate files of tables and points that control navigation. Finally, it should be capable of creating the ISO-9660 and micro-UDF file systems required by the DVD spec and of writing them to disc or tape.
In the authoring phase, DVD authoring software generally provides an environment in which to construct clips of video and audio, which may include multiple audio streams, subtitles in varied languages, and scene-access points. A DVD-Video may include as many as 99 video clips or movies. As noted before, a DVD-Video clip can consist of audio with a single still picture as a placeholder when video is not required.
Most authoring software packages provide a separate editing environment for creating menu screens. It is generally a two-dimensional graphic editor that lets you place graphics, define button target areas, choose highlight colors that indicate selected buttons, and determine the behavior of the menu in response to the DVD-remote controls. DVD menus are sometimes used as viewer-controlled slides. In some titles, the number of individual menu screens reaches into the hundreds, although a dozen or so is more typical. If you are looking at a low-cost DVD authoring program, check for restrictions on the number of menus allowed.
The authoring software must also have a way to define the order in which different elements appear and how menu buttons connect to video clips or other menus. Some authoring packages do this by providing for entry of a command at the end of each video clip and each menu button. Other packages provide a tabular display of navigation connections, with drag-and-drop linking from a Source to a Destination.
Flowcharts and tabular views have strengths in different situations. Flowcharts make it easy to visualize simple structures but can become overcrowded when project complexity increases. Tabular views are less intuitive for simple work but have scaled up very well to the most difficult and complicated titles. It's worth considering the method of linking used in any authoring package you look at. Even relatively simple DVD titles can have dozens of individual links, and you want to be able to make those connections and review them easily.
Interactive scripting may not be a concern, but mid- to high-priced DVD authoring products support programming in the language defined by the DVD spec. That provides a set of machine-code-like instructions that accept user input, do math functions, store data, and make condition jumps to video clips or menus based on values stored in memory. The biggest limitation to interactive coding, however, is that the memory storage space is extremely limited, with a maximum of 16, 16-bit registers available.
Q.A. VIA SIMULATION
With all of the options available, creating DVD titles can get genuinely complex. Even simple titles have ample room for authoring errors. It's extremely important to see how your project will play before you commit it to disc. DVD-R media are getting more affordable, but not so much that you want to waste materials in order to find problems that could have been easily corrected prior to burning.
Any DVD authoring package worth having provides a means to simulate your DVD title during the authoring phase so you can test navigation links and verify that the media and behavior of the disc work as intended. The simulator typically provides debugging information such as the values of internal variables and the player's internal state.
Many packages also provide a way to review a title from hard disk after it has been compiled into the DVD-data format but before it is committed to disc. That is usually called emulation and consists essentially of playing the DVD content on hard disk using a standard DVD-player application.
Once audio-video clips and navigation menus are configured, connected, and checked by simulation, the data has to be compiled into the specific forms required for DVD playback, as defined by the DVD spec. Most authoring packages compile data to hard disk, creating a complete data set equal in size to the finished DVD. That requires you to have a block of free hard-disk space equal to the size of your project. Some recent authoring systems, however, are capable of formatting as they write to disc, which can save hard-disk space and time.
Most of the compiling time goes toward multiplexing video, audio, and subtitle data into a single composite stream. When a DVD player plays a selection, it reads the multiplexed data from the disc and reassembles it in the player's internal buffer while ignoring data from inactive video, audio, or subtitle streams. Without that elaborate multiplexing scheme, DVD playback wouldn't work.
The second part of the compiling process consists of generating the files (which are tiny compared with the gigabytes of audio and video information) that control the disc's navigation and behavior. Those files are defined down to the bit by the DVD-Video spec and are highly elaborate, incorporating information about the disc in forms that can be understood by any player in the world.
Finally, the DVD data structure must be incorporated into a disc image that embodies the ISO-9660/micro-UDF Bridge file system defined for DVD. In most systems, that final formatting operation is performed while data is being written to DVD-R or to DLT tape for mastering and replication.
LET'S GO SHOPPING
Because DVD-Video authoring has been a growing concern for a few years, the software products are comparatively mature. At the same time, the business is in transition from its commercial phase, in which authoring products were purchased by only a relatively small number of professional service providers, to a phase in which desktop musicians can afford them.
As a result, DVD-Video authoring products on the market span a huge range of price and functionality. With little agreement as to what features are most appropriate at a given price point, shopping for DVD authoring software can be daunting.
Selecting the right DVD authoring tool will depend on the applications you have in mind, your budget, your preferred platform (PC or Mac), and your feeling for the style and philosophy of a vendor's offerings. Authoring programs also vary in stability, a quality that doesn't come across in manufacturer's data. Trade notes with people who are using a manufacturer's products before making a decision.
PRODUCT TIERS AND TYPES
The field of DVD production tools is in flux, and manufacturers are rapidly adjusting their products to meet the emerging needs of content producers. In general, software for creating DVD-Video falls into four general categories. Personal DVD-authoring software is often priced less than $200 and is easy to use, but it is sharply limited in function. Entry-level commercial software has a pro-style user interface — usually with a constrained feature set — and is priced from a few hundred dollars to $1,000.
In the several-thousand-dollar range are the midpriced commercial systems. They are robust products with a wide range of capabilities, though they may lack features used primarily for commercial DVD releases. The optional hardware encoding devices can raise the price even higher. Fully professional DVD production systems usually offer full support of the DVD spec and integrated high-end encoding. Their prices are in the tens of thousands of dollars.
As you may suspect, the product categories can overlap. Because manufacturers position their products differently, basing your purchases on data sheets alone is not recommended. To ensure you make the right selection, ask questions, exchange information with product users, and test the software in a realistic production situation.
Depending on your application and the functions included in the authoring package you select, you might need additional dedicated software or hardware products for video and audio encoding. Although a complete survey of specific products is beyond the scope of this article, the sidebar “DVD Authoring Sources” lists a number of suppliers of DVD-Video and DVD-Audio authoring programs, video- and audio-encoding tools, and DVD data-formatting software. Note that many of a software tool's most important qualities — such as completeness, style of interaction, and scalability — are unlikely to be reflected in the manufacturer's literature.
The viability of DVD technology in the personal studio is poised to increase dramatically. Although DVD-Audio software and player population are still relatively undeveloped and priced for pro-level budgets, the DVD-Video format offers a wealth of possibilities for musicians. But personal-studio musicians need to select their authoring tools carefully to make sure that the features they need are included.
Musicians are at the threshold of a brave new audio-reproduction world that is equal in importance to the introduction of the CD. DVD technology may seem out of your reach now, but rest assured that it won't be for long.
Gary Hall is a former technical editor for EM. He has been working with professional digital-audio and video production gear since the late '70s. He is manager of professional DVD authoring products for Spruce Technologies in San Jose, California.
DVD-Video and DVD-Audio Capabilities
This table summarizes the features of the DVD-Video and DVD-Audio formats. Although DVD-Audio offers superior fidelity for surround applications, DVD-Video players and tools are far more prevalent and affordable.
DVD-Video DVD-Audio Audio Features
PCM stereo resolution and sampling rateUp to 24-bit at 96 kHzUp to 24-bit at 192 kHzMultichannel surround optionsData-compressed in Dolby AC-3 or DTS format from 16- or 24-bit source at 48 kHzPCM up to 24 bits at 96 kHz, with MLP lossless compression
High-grade full-motion videoYesNoSlide-show featuresKeyed to time and not advanceable by user without interrupting audioStill pictures may be advanced or accessed randomly while audio plays
Alternate audio streams81Alternate subtitle or graphic streams321Alternate visual angles91 (still only)
Still menusYesYesMotion menus and transitionsYesNoRandom selection during playYesYes
Options for Interactivity
Built-in scripting languageYesNo
DVD Capacity and Nomenclature
For a number of reasons (including marketing considerations), the data capacity for DVD discs is nearly always stated in billions of bytes, which is represented by a G, rather than in computer gigabytes (GB). That can lead to confusion because a gigabyte (1,073,741,824 bytes) is significantly larger than a billion bytes.
The stated capacities for various forms of replicated and recordable DVD may therefore be less than you think. The table below lists several forms of DVD — replicated and recordable — and their data capacities in gigabytes and billions of bytes. I've intentionally omitted double-sided forms of DVD from the table.
Most of the computer operating systems we use today (the various forms of Windows and the Mac OS) list the sizes of files and directories both in gigabytes and in absolute byte count. When assessing the size of a file or directory that you want to put on DVD, always look at the absolute byte count, and you won't go wrong.
Capacity in G
(billions of bytes) Capacity in GB
DVD-R Authoring 3.95G3.95G3.678 GBDVD-R Authoring 4.7G4.7G4.377 GBDVD-R General4.7G4.377 GB
DVD-5 (single-sided/single-layer)4.7G4.377 GBDVD-9 (single-sided/dual-layer)8.54G7.953 GB
Delve further into the worlds of DVD and DVD-recordable technology with these references.
DVD Demystified, 2nd ed.
By Jim Taylor (McGraw-Hill, 2001; $49.95)
This is the original (and only) general reference to DVD available to the general public. The second edition includes information about DVD production methods and DVD-Audio that is not found in the original. If you are serious about DVD, you need this book.
Available from DVD Forum (www.dvdforum.org; $5,000).
The complete arsenal of DVD specs is available for a mere $5,000 and the signing of a really stiff nondisclosure agreement. Its several hundred pages of incredibly dense information are not for the faint of heart.
Jim Taylor's DVD FAQ is a rich source of information. The data overlaps with that presented in his book DVD Demystified, but it is subject to frequent updates.
Mark Johnson, one of the most knowledgeable and experienced DVD producers, has aimed his site directly at those who are producing DVD content. Free membership gives you access to a range of articles and forums.
DVD AUTHORING SOURCES
The companies listed below make and sell the specialized products discussed in this article. The types of products and (where applicable) the platforms supported are described.
Audio Cube (www.sascom.com): DVD-Audio authoring software (Win), digital-audio workstations (DAWs; Win).
AuthoringWare (www.authoringware.com): DVD-Video authoring software (Win), DVD-ROM formatting software (Win).
Canopus (www.canopuscorp.com): video editing systems (Win), video- and audio-encoding products (Win).
Gear Software (www.gearsoftware.com): DVD-ROM formatting and writing software (Win).
Heuris (www.heuris.com): video- and audio-encoding software (Mac/Win).
Intec America (www.inteca.com): DVD-Video authoring software (Win), DVD-ROM formatting software (Win).
Interactual (www.interactual.com): DVD Web-linking technology.
Matrox (www.matrox.com): video editing systems (Win), video- and audio-encoding products (Win).
Minnetonka Audio (www.minnetonkaaudio.com): DVD-Audio authoring software (Win), audio-encoding software for AC-3 and DTS (Win), 5.1-audio-production software (Win).
Panasonic (www.panasonic.com): DVD burners.
Pioneer New Media Technologies (www.pioneerprodj.com): DVD burners.
Pinnacle Systems (www.pinnaclesys.com/professionaldivision.asp): DVD-Video authoring software (Win), video editing systems (Win), video- and audio-encoding products (Win).
Prassi (www.prassieurope.com): DVD-ROM formatting and writing software (Mac/Win).
Roxio (www.roxio.com): DVD-ROM formatting and writing software (Mac/Win).
Sadie (www.sadieus.com): DVD-Audio authoring and MLP encoding software (Win), DAWs (Win).
Sonic Solutions (www.sonic.com): DVD-Video authoring software (Mac/Win), DVD-Audio authoring software (Mac), video- and audio-encoding hardware and software (Mac/Win), DVD Web-linking technology, DAWs (Mac), DVD-ROM formatting software (Mac).
SpinWare (www.spinware.net): DVD Web-linking technology.
Spruce Technologies (www.spruce-tech.com): DVD-Video authoring software (Win), video- and audio-encoding hardware (Win), DVD Web-linking technology tools, DVD-ROM formatting software (Win).
Vitec Multimedia (www.vitecmm.com): video- and audio-encoding hardware and software (Win).