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HD on DVD -- Better Video, More Storage (2/2005)
by Douglas Dixon
High-def is hot! You can watch HD -- Consumers are stampeding to HDTV, with cool flat-panel LCD and plasma displays. And you can shoot and edit HD -- Videographers are stepping up to new HDV cameras from JVC and Sony, and then capturing and editing in HD formats using the latest upgrades of desktop editing software. But what about delivery? How can you distribute and display that great high-definition content?
What happened to high-def DVD anyway? How are we supposed to record and watch HDTV broadcasts and movies on our home entertainment centers? And even for data storage, plain old DVDs with 4.7 GB of storage are starting to look awfully cramped for archiving video files. We need more storage!
The good news is that relief is coming soon, in the form of high-def DVD discs that use blue-laser technology to squeeze 15 to 20 GB of data per disc layer. The bad news is that we are facing yet another DVD "format war" -- this time between the incompatible HD DVD and Blu-ray Disc formats.
But don't despair: you don't have to wait for new technology -- you actually can deliver and display HD content today, on plain old DVD discs, with Microsoft's Windows Media Video HD format.
Confused yet? Let's take a look at the high-def DVD landscape, and see if we can shine some light on both the promise of the glorious blue-laser future, as well the additional possibilities of the red-laser present.
DVD is being stressed by our storage needs, particularly with high-def content. Moving from standard-definition video (720 x 480) to HD (1920 x 1080) requires a 6X jump in capacity and data rate. But we'd still like to keep the convenient form factor of those shiny discs, and we'd like players that are backward compatible with CD and DVD.
One solution is to move to higher-density storage. CD was introduced in the mid 1980s, blowing away floppy discs as a data archive format with a whopping 780 MB capacity. DVD was introduced in the mid 1990s, and stepped up to 4.7 GB, offering 6X more storage in the same disc size by moving from a infra-red to a smaller-wavelength red laser (780 to 650 nm). Another decade later, we're ready for the next jump in capacity by moving to a blue laser (405 nm) to make even more teeny tiny data bits on the discs, permitting another 3X to 5X jump in data density to 15 to 20 GB.
The other trick in fitting HD data on discs is to not only increase the raw data capacity of the discs, but also to squeeze the video harder with more aggressive data compression. After all, there have been significant advances in video compression technology since MPEG-2 was developed in the mid-1990s. Formats like MPEG-4 and Windows Media Video now offer the same quality with 3X to 6X better compression, which means it's feasible to compress high-def material to around the same data rates that we're used to using for standard-definition material.
Which leads us to the major philosophical difference between the two contending formats: HD DVD is a more conservative design that supports 15 GB per disc. Its boosters argue that this bump in capacity, along with better compression, is enough to deliver HD movies on disc. In comparison, Blu-ray Disc pushes the disc density up to 20 GB. Its supporters argue that that more data capacity is better, and that we'll certainly find ways to take advantage of it. Both formats are also looking beyond single-layer discs to double-layer formats for double the capacity -- to 30 or 50 GB. That's really getting interesting! (You may see other slightly different sizes for read-only and rewritable variants.)
Above the physical disc structure, the two formats have rather similar approaches for the audio/video content. Both will support MPEG-2, MPEG-4 (AVC), and Microsoft Windows Media (VC-1) video formats, and variants of Dolby Digital audio. And both intend to support greatly expanded interactivity, beyond DVD's simple menus and buttons to a more Flash-like programmable interface. This should allow much more dynamic interfaces, mixing video content with text and graphics, full games and interactive activities, and built-in Web access for dynamic updates.
The HD DVD format is championed by Toshiba and NEC (www.hddvdprg.com), and has been approved by the DVD Forum, the industry consortium that established the base DVD formats (www.dvdforum.org). Since it is a more conservative design, a major benefit claimed for HD DVD is lower manufacturing cost from re-using more of existing lines.
The Blu-ray Disc (BD) format is being developed by a powerful group of companies that overlaps the membership of the DVD Forum (www.blu-raydisc.com). These include consumer electronic giants (Hitachi, LG Electronics, Matsushita, Panasonic / Mitsubishi Electric, Pioneer, Philips, Samsung, Sharp, Sony and Thomson), media manufactures (including TDK and Technicolor), and major PC manufacturers (with Hewlett-Packard and Dell).
Both camps are busily working on the entire infrastructure of manufacturing discs, running test lines to shake out the equipment and processes, and to predict manufacturing costs. Early Blu-ray consumer products are actually on the market in Japan, including HD video recorders / players from Panasonic, Sharp, and Sony. This blue laser technology is also being used for Sony's ProData (Professional Disc for Data) high capacity 23 GB professional optical storage format (drives list at $2400, media around $45; www.sonyburners.com/prodata).
Sony ProData media
Both formats are gearing to reach the market at the end of 2005 and in 2006, so it looks like we're going to have yet another confusing battle of DVD formats. With all this effort invested in the two formats, do not expect a miraculous last-minute agreement to settle on one common standard.
The DVD industry has survived the dash vs. plus format confusion (from DVD-R to +RW), calming the issue by developing dual-format drives to burn either disc format, which than should be readable on any DVD player. However, blue laser is more of a VHS vs. Beta situation, with physically incompatible formats that not only must be recorded on the appropriate device, but which only can be played back on a compatible player. Also like VHS/Beta, the developers of these formats intend that the initial products be combination player/recorders, not just players for pre-recorded movies as with the release of DVD.
While conflicting formats arguably could be less of an issue for DVD recorders that are used to time-shift off-air HDTV broadcasts, it obviously is a huge issue for the business of selling prerecorded movies on DVD as a mass-market product. As a result, the content owners, the Hollywood studios, have a huge influence on the success of these formats. The studios need to be satisfied with the content protection technology in order to support the formats for distributing their films in digital high-def quality. Unfortunately, unlike the case with DVD, there is no strong enough voice to get the camps to come together to support a common format. As a strong Blu-ray Disc supporter, Sony brings its Columbia Pictures studio, plus its recipient acquisition of MGM. And the HD DVD camp announced support from other studios in November 2004: Viacom's Paramount, GE's Universal Studios, and Time Warner's Warner Bros. and New Line Cinema (though these agreements are not necessarily exclusive). Here we go again with multiple formats ...
Just to add further confusion to the mix, China is reported to be developing its own DVD format called Enhanced Versatile Disk (EVD), in order to avoid the overhead of DVD licensing fees. And in November 2004 New Medium Enterprises announced a Versatile MultiLayer Disc (VMD) format that provides 20 GB of capacity using red laser technology. The discs just keep on coming.
However, there's another perspective on this race to introduce new competing high-capacity formats. If the most critical need is simply to fit a two-hour movie on a disc in HD, then we don't necessarily need a new physical disc at all -- compression technology has advanced far enough in the last decade beyond MPEG-2 to give us the improvement needed to support HD on standard DVD discs.
The MPEG-4 standard was standardized by ISO/IEC in 1998-99 to extend MPEG-2 for this kind of purpose, including use in digital television, Web streaming, and interactivity (www.chiariglione.org/mpeg). While the MPEG-4 format is finding strong use in wireless streaming applications, deployment has been hampered by licensing issues. In addition, compression technology then leapt ahead again with proprietary formats like Windows Media, so MPEG-4 was updated to MPEG-4 AVC (Advanced Video Codec).
Apple has made MPEG-4 the core format of QuickTime version 6, which has become the most accessible method for viewing and creating MPEG-4 material on the desktop -- Widows video tools now commonly export to MPEG-4 through QuickTime (www.apple.com/quicktime).
Meanwhile, when Microsoft introduced the Windows Media 9 Series platform in 1999, it included significantly enhanced video and audio compression technology for encoding video at around 1/3 the size of MPEG-2 (www.microsoft.com/windowsmedia). It was also designed to be highly scalable, supporting not only consumer, desktop and Web usage, but also down to small handheld devices, and up to high definition professional applications.
Windows Media High Definition Video (WMV HD), then, is video compressed at 720p resolution and higher (i.e., starting at 1280 x 720 progressive). Microsoft also introduced an Advanced Profile codec in late 2004 that improves support for interlaced content and for transmitting WMV material for broadcast and wireless. The Windows Media Audio 9 Professional codec also provides high-fidelity 5.1 channel sound (and even 7.1 channel), delivering full surround-sound audio at data rates typically used for MP3 audio.
As a result, WMV HD has become a defacto delivery format for high-def presentations, avoiding the issues of requiring specific formats of professional HD media and gear. WMV is easy to encode, using the Windows Media format support built in to most video editing software, or the free stand-alone Windows Media Encoder (www.microsoft.com/windows/windowsmedia/9series/encoder). Plus it's easy to present on today's PCs, since computer displays have resolutions at HD range and beyond. Even better, you can connect a PC up to a projector and display your HD content in large venues. (Microsoft does recommend a minimum configuration of a 2.4 GHz processor, and an optimum configuration of 3.0 GHz machine with 512 MB memory, 1920 x 1440 display, and 24-bit 96 kHz multi-channel sound card to play 1080p video with 5.1 surround sound.)
But we're talking about DVD here, and this level of compression also means that HD material can fit on a regular DVD, and also can be played back directly from a disc. To experiment with this possibility, Microsoft has worked with the studios to add full HD versions of movies as a bonus feature with several releases, including "Standing in the Shadows of Motown" and "Terminator 2: Judgment Day" (see www.wmvhd.com). Nine IMAX films have also been released in this format, with the traditional DVD movie on one disc, and the WMV HD version on a second disc.
One you've delivering video, and movies, on a DVD disc, however, it needs to be more than just linear video -- viewers expect a DVD-like experience, with menus and buttons and navigation. Microsoft has been evolving such an interface for WMV HD DVDs, as demonstrated by the "Coral Reef Adventure" IMAX DVD.
Coral Reef Adventure IMAX DVD
One disc contains a "regular" DVD with the 47-minute movie in standard definition, stored in both full-frame 4x3 and widescreen 16x9 formats in 7 GB (on a dual-layer disc). The second disc then has two more copies of the film, in high definition, stored in about half the space: 720p in 2.1 GB (around 6.4 Mbps) and 1080p in 2.7 GB (8.4 Mbps).
The high-def Coral Reef disc starts up automatically with a full-screen movie-watching experience. After the FBI warning and studio logos, it displays a beautiful full-screen main menu (after all, a PC monitor has much higher resolution than a DVD on your TV screen). Like a DVD, the menu buttons highlight when you mouse over them. And they do more: when you mouse over a button on the Chapter Menu, it also simultaneously updates other areas of the menu to display a larger image and text information about the chapter.
Coral Reef: Chapter Menu
You also can use the Disc Options menu to set up and test your 5.1 surround-sound audio, and to choose the video playback resolution: 720p (1280 x 720) or full 1080p (1920 x 1080). The enhanced menus even analyze your system performance and recommends the optimal resolution for smooth playback.
Coral Reef: HD Setup Menu
These discs do use the Windows Media Digital Rights Management (DRM) technology to protect the content from being copied. The studios have typically provided a free license for playback, but required that it be updated through an Internet connection approximately weekly.
Around the end of 2004, Sonic introduced DVD Producer HD, the first authoring tool expressly designed for authoring WMV HD DVD discs ($12,999; www.sonic.com/dvdproducerhd). DVD Producer HD extends the usual authoring interface to support working with WMV HD assets, designing menus at high-def resolution, and providing the extra level of interactivity for buttons and navigation. Sonic also has extended its hardware encoder product line to add the HD-series real-time WMV HD Encoder.
DVD has had a great run in the first half of this decade, both as a consumer product for movie viewing and as a computer product for data storage -- even with the dash / plus format confusion and the delay in introducing DVD recorders. But this wonderful period of stability building on a single, common format is coming to an end. The future of higher-definition video and higher-capacity discs is going to be messier for all of us: movie viewers, video editors, and DVD authors.
The new blue-laser formats, Blu-ray Disc and HD DVD, will certainly provide a welcome bump in capacity from 4.7 GB to 15 or 20 GB, and then beyond with dual-layer discs. And better compression formats such as MPEG-4 and Windows Media Video HD allow us to squeeze more and higher-res material on our discs, whatever their size.
Microsoft is actually positioning WMV as a bridge format across all these possibilities. A version of WMV9 called VC-1 has been submitted for standardization by SMPTE, and also has been accepted as one of the video formats to be used for both Blu-ray and HD DVD.
So the future is red -- and blue. We can start preparing for it now, but we'll also have to see how it plays out over the next couple of years in this battle of laser weapons.
Blu-ray Disc Association (BD)
HD DVD Promotion Group
Sony - ProData - Professional Disc for Data
MPEG Committee - Moving Picture Experts Group
MPEG Industry Forum - MPEGIF
Apple - QuickTime 6
Microsoft - Windows Media
Windows Media High Definition Video (WMV HD)
Windows Media Encoder
Sonic - DVD Producer HD