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Published: 2009-02-24 - 21:27:49
Home Theater : Ask The Expert

What Is Blue Ray Technology?

By Chris Chiarella

Question:

Today's topic comes up so frequently, albeit in a variety of different forms, that rather than attribute it to a single reader, we'll thank everyone and try to address, once and for all, "What is Blu-ray?" or "What is Blue Ray Technology?" as many of the online curious tend to express it. While Blu-ray Disc (as the format is officially known and spelled) has undoubtedly made a foothold in the consumer electronics world, it is continuing to grow, and many home theater buffs want to know more about this magic silver disc before taking the plunge.


Answer:

"The successor to DVD" is one way of looking at Blu-ray, the victor in the war with former rival HD DVD is another. The simplest truth is that it is the latest consumer-available optical disc format, a means of delivering movies and other audio/video content in full 1080p high-definition on packaged media. Blu-ray hardware and software have been on the market here in the United States since 2006, but had their biggest explosion in popularity with the otherwise lackluster holiday shopping season of 2008.

Co-developed by Sony, Philips and Pioneer, Blu-ray Disc--also known as Blu-ray or simply "BD" for short--takes its name from the blue laser pickup (actually violet-colored) which reads the digital data stored on the disc. Owing to the shorter wavelength of the blue laser, data can be more densely packed on a Blu-ray than on a red-laser DVD. The data layer is also closer to the surface of a Blu-ray disc.

Storage Space... The Final Frontier

A maximum of 17 gigabytes of storage is possible on DVD, assuming dual-layer and dual-sided, although these double-sided discs never really caught on.  More commonly available are the single sided DVDs which handle approximately 4.7 GB or 8.5 GB for single and dual layered discs, respectively.

blu-ray-logo-med.jpg
There is no "e" in Blu-ray.
Meanwhile Blu-rays commonly pack up to 50 gigabytes on a single side, dual-layered disc, and there is talk of blue laser optical discs potentially storing as much as 500GB at some point. More data storage means higher quality first and foremost, capable of sustaining higher bitrates for the entire running time. Higher bitrates generally translate to higher audio/video resolution and better color depth as more data is being processed each second, better rendering crucial fine A/V detail for a more richly realized, more cinematic presentation.  This extra detail and enhanced color becomes particularly noticeable on a large screen flat panel HDTV or home theater projection screen.

To fit an entire full-length high definition feature film onto a five-inch disc along with plenty of special features, Blu-ray generally uses one of two approved video compression schemes, or codecs. AVC ("Advanced Video Coding"), a sophisticated flavor of MPEG-4, is a more efficient version of the common MPEG-2 video compression found on DVDs and elsewhere. Put another way, a properly authored AVC file can deliver superior video quality at lower bitrates than previously possible, an ideal combination for the convenience of Blu-ray discs while meeting the expectations of high-definition. The other option is VC-1, a video format co-developed by Microsoft, a variation upon their Windows Media Video codec which offers high compression but minimal signal loss in the encode/decode process.  Both of these formats are options for the studios when creating their Blu-ray discs, and most of us uber-geeks here at Big Picture Big Sound have personally reviewed both AVC- and VC-1-encoded discs and each codec is capable of producing excellent results when implemented properly.

When content such as the pre-existing bonus features from a DVD release are simply ported over to Blu-ray in standard definition, they are presented in the original MPEG-2 format. All Blu-ray players are fully backward compatible to support DVD, and most players, except the very early ones, support CD playback as well.  Blu-ray players also generally perform "upconversion" of 480p standard-definition DVDs to quasi-HD levels, with varying degrees of success, all the way up to 1080p resolution.  A good Blu-ray player can make regular DVDs look pretty darn good.

Big Picture... BIG SOUND

Blu-ray also enables new high-definition audio formats, which can be identical to what the Hollywood sound engineers hear in the studio when mixing the movie for theaters. The storage space of the disc and the decoding power of the player--combined with and the latest A/V receivers--make this quality possible. The competing DTS-HD Master Audio and Dolby TrueHD codecs are each capable of reproducing up to 7.1 discrete channels of audio more accurately and with greater dynamic range than ever before achievable in the home.  These formats do use compression to shrink the bandwidth and storage requirements but they do it in a "lossless" manner which means these soundtracks are bit perfect copies of the original digital PCM master tapes.

More Profiles than a Facebook Addict

Enhanced interactivity was also one of the promises of Blu-ray, which has only improved since launch. The evolution to BD-ROM Profile 1.1 added "Bonus View" picture-in-picture, one or more optional video streams that can appear as a smaller window over the movie for behind-the-scenes footage, filmmaker interviews, etc. To support this feature, a player must have a second dedicated video decoder, and so most first-generation players needed to be replaced if a consumer wanted the benefits of Profile 1.1.

BD-ROM Profile 2.0 later brought support for BD-Live, a further series of studio-supported, updatable bonus features via the internet, in addition to access to an online community. Here again, many of the Profile 1.1 players could not support 2.0, because an Ethernet port (or Wifi connection) had to be included in the hardware for high-speed internet access. Players also needed to be able to store, at least temporarily, varying amounts of new data--at least 1 Gigabyte worth of data, to be precise--but a plug-in USB flash drive or SD card (depending on the model) can usually do the trick.

But early adopters of the format have been a bit frustrated by the need to upgrade the hardware just to keep up with the latest software features.  The good news is that most Blu-ray players available today support the full BD-ROM 2.0 Profile (look for that "BD-Live" logo), and the network ports on these players enable them to be upgraded by the manufacturer in order to fix bugs or enable new features.  This makes them about as future-proof as can be expected from any CE device.

The one notable exception to this built-in obsolescence is the Sony PlayStation 3, a Blu-ray-based game console with a powerful processor and wired or wireless internet access (depending upon model) across the entire line. PS3 offers a minimum of 20GB of hard disk drive space, and Sony continually pushes free, easy-to-acquire firmware updates to add new features (such as Bonus View and BD-Live) and refine old ones. And its video performance is simply outstanding.  And by the way, it also plays movies.

Java software support is mandatory as part of the Blu-ray spec, here called BD-J or BD-Java to represent the true interactivity it brings to the elaborate pop-up disc menus, as opposed to pre-rendered animated menus on DVD. Certain next-generation set-top games also take advantage of BD-J technology. Blu-ray offers new refinements we can actually feel, too, including the harder, vastly more durable outer layer developed by the blank media mavens at TDK, which makes it better-suited for rental than the more scratch-prone DVD. Not surprisingly, Blu-ray rentals are booming over at Netflix.

Where to Buy:

This model is similar to what I use as my primary Blu-ray player:

(My precise model, from the first-generation of PS3s, is no longer manufactured.)

And for triple-secret bonus points, always spell Blu-ray with a capital B, no e, a hyphen and a lower-case r!

You can find out more about Blu-ray right here on Big Picture Big Sound:

Enjoy,

--Chris C.

Current Hot Titles on Blu-ray Disc (Amazon.com):

Keep those cards and letters coming! if you have a question for one of our home theater experts, shoot us an e-mail to "Ask The Expert." We'll select among these for future installments in this column. Due to the volume of requests we receive, we cannot reply to each question personally.

What do you think?

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