Blu-ray FAQ





General





Blu-ray vs DVD





Blu-ray movies





General





Blu-ray, also known as Blu-ray Disc (BD) is the name of a new optical disc format that is rapidly replacing DVD. The format was developed to enable recording, rewriting and playback of high-definition video (HD), as well as storing large amounts of data. The format offers more than five times the storage capacity of traditional DVDs and can hold up to 25GB on a single-layer disc and 50GB on a dual-layer disc. For more general information about Blu-ray, please see our What is Blu-ray? section.



The name Blu-ray is derived from the underlying technology, which utilizes a blue-violet laser to read and write data. The name is a combination of "Blue" (blue-violet laser) and "Ray" (optical ray). According to the Blu-ray Disc Association the spelling of "Blu-ray" is not a mistake, the character "e" was intentionally left out so the term could be registered as a trademark.



The correct full name is Blu-ray Disc, not Blu-ray Disk (incorrect spelling)

The correct shortened name is Blu-ray, not Blu-Ray (incorrect capitalization) or Blue-ray (incorrect spelling)

The correct abbreviation is BD, not BR or BRD (wrong abbreviation)





The Blu-ray Disc format was developed by the Blu-ray Disc Association (BDA), a group of leading consumer electronics, personal computer and media manufacturers, with more than 180 member companies from all over the world. The Board of Directors currently consists of:



Apple Computer, Inc.

Dell Inc.

Hewlett Packard Company

Hitachi, Ltd.

LG Electronics Inc.

Matsushita Electric Industrial Co., Ltd.

Mitsubishi Electric Corporation

Pioneer Corporation

Royal Philips Electronics

Samsung Electronics Co., Ltd.

Sharp Corporation

Sony Corporation

Sun Microsystems, Inc.

TDK Corporation

Thomson Multimedia

Twentieth Century Fox

Walt Disney Pictures

Warner Bros. Entertainment





As with conventional CDs and DVDs, Blu-ray plans to provide a wide range of formats including ROM/R/RW. The following formats are part of the Blu-ray Disc specification:



BD-ROM - read-only format for distribution of HD movies, games, software, etc.

BD-R - recordable format for HD video recording and PC data storage.

BD-RE - rewritable format for HD video recording and PC data storage.



There's also plans for a BD/DVD hybrid format, which combines Blu-ray and DVD on the same disc so that it can be played in both Blu-ray players and DVD players.



A single-layer disc can hold 25GB.

A dual-layer disc can hold 50GB.



To ensure that the Blu-ray Disc format is easily extendable (future-proof) it also includes support for multi-layer discs, which should allow the storage capacity to be increased to 100GB-200GB (25GB per layer) in the future simply by adding more layers to the discs.



Over 9 hours of high-definition (HD) video on a 50GB disc.

About 23 hours of standard-definition (SD) video on a 50GB disc.







According to the Blu-ray Disc specification, 1x speed is defined as 36Mbps. However, as BD-ROM movies will require a 54Mbps data transfer rate the minimum speed we're expecting to see is 2x (72Mbps). Blu-ray also has the potential for much higher speeds, as a result of the larger numerical aperture (NA) adopted by Blu-ray Disc. The large NA value effectively means that Blu-ray will require less recording power and lower disc rotation speed than DVD and HD-DVD to achieve the same data transfer rate. While the media itself limited the recording speed in the past, the only limiting factor for Blu-ray is the capacity of the hardware. If we assume a maximum disc rotation speed of 10,000 RPM, then 12x at the outer diameter should be possible (about 400Mbps). This is why the Blu-ray Disc Association (BDA) already has plans to raise the speed to 8x (288Mbps) or more in the future.



MPEG-2 - enhanced for HD, also used for playback of DVDs and HDTV recordings.

MPEG-4 AVC - part of the MPEG-4 standard also known as H.264 (High Profile and Main Profile).

SMPTE VC-1 - standard based on Microsoft's Windows Media Video (WMV) technology.



Please note that this simply means that all Blu-ray players and recorders will have to support playback of these video codecs, it will still be up to the movie studios to decide which video codec(s) they use for their releases.



Linear PCM (LPCM) - up to 8 channels of uncompressed audio. (mandatory)

Dolby Digital (DD) - format used for DVDs, 5.1-channel surround sound. (mandatory)

Dolby Digital Plus (DD+) - extension of Dolby Digital, 7.1-channel surround sound. (optional)

Dolby TrueHD - lossless encoding of up to 8 channels of audio. (optional)

DTS Digital Surround - format used for DVDs, 5.1-channel surround sound. (mandatory)

DTS-HD High Resolution Audio - extension of DTS, 7.1-channel surround sound. (optional)

DTS-HD Master Audio - lossless encoding of up to 8 channels of audio. (optional)



Please note that this simply means that Blu-ray players and recorders will have to support playback of these audio codecs, it will still be up to the movie studios to decide which audio codec(s) they use for their releases.



No, the development of new low cost hard-coating technologies has made the cartridge obsolete. Blu-ray will instead rely on hard-coating for protection, which when applied will make the discs even more resistant to scratches and fingerprints than today's DVDs, while still preserving the same look and feel. Blu-ray also adopts a new error correction system which is more robust and efficient than the one used for DVDs.



No, you will not need an Internet connection for basic playback of Blu-ray movies. The Internet connection will only be needed for value-added features such as downloading new extras, watching recent movie trailers, web browsing, etc. It will also be required to authorize managed copies of Blu-ray movies that can be transferred over a home network.



No, Blu-ray players will not down-convert the analog output signal unless the video contains something called an Image Constraint Token (ICT). This feature is not part of the Blu-ray Disc spec, but of the AACS copy-protection system also adopted by HD-DVD. In the end it will be up to each movie studio to decide if they want to use this "feature" on their releases or not. The good news is that Sony, Disney, Fox, Paramount, MGM and Universal have already stated that they have no intention of using this feature. The other studios, which have yet to announce their plans, will most likely follow suit to avoid getting bad publicity. If any of the studios still decide to use ICT they will have to state this on the cover of their movies, so you should have no problem avoiding these titles.



Yes, mandatory managed copy (MMC) will be part of the Blu-ray format. This feature will enable consumers to make legal copies of their Blu-ray movies that can be transferred over a home network. Please note that "mandatory" refers to the movies having to offer this capability, while it will be up to each hardware manufacturer to decide if they want to support this feature.



If you live in the US or Canada you can already find Blu-ray players from Samsung, Panasonic, Sony, Philips and Pioneer available in stores, as well as a growing selection of Blu-ray movies. We also expect to see Blu-ray players from LG and Sharp, as well as a second-generation Blu-ray player from Samsung introduced in the near future. The first Blu-ray hardware and software should also be available in many European countries now.



As with any new technology the first generation of products will likely be quite expensive due to low production volumes. However, this shouldn't be a problem for long as there is a wide range of Blu-ray related products (players, recorders, drives, writers, media, etc) planned, which should help drive up production volumes and lower overall production costs. Once mass production of components for Blu-ray products begins the prices are expected to fall quickly.



According to the Blu-ray Disc Association, the overall cost of manufacturing Blu-ray Disc media will in the end be no more expensive than producing a DVD. The reduced injection molding costs (one molding machine instead of two, no birefringence problems) offset the additional cost of applying the cover layer and low cost hard-coat, while the techniques used for applying the recording layer remain the same. As production volumes increase the production costs should fall and eventually be comparable to DVDs.







Blu-ray vs DVD





Yes, that's the expectation. The Blu-ray format has received broad support from the major movie studios as a successor to today's DVD format. In fact, seven of the eight major movie studios (Disney, Fox, Warner, Paramount, Sony, Lionsgate and MGM) have released titles in the Blu-ray format. Many studios have also announced that they will begin releasing new feature films on Blu-ray Disc day-and-date with DVD, as well as a continuous slate of catalog titles every month. For more information about Blu-ray movies, check out our Blu-ray movies section which offers information about new and upcoming Blu-ray releases, as well as what movies are currently available in the Blu-ray format.



However, the two formats (Blu-ray and DVD) will most likely co-exist for quite some time until HDTVs become more widespread.



Yes, several leading consumer electronics companies (including Sony, Panasonic, Philips, Samsung, Pioneer, Sharp and LG) have already demonstrated products that can read/write CDs, DVDs and Blu-ray discs using a BD/DVD/CD compatible optical head, so you don't have to worry about your existing DVD collection becoming obsolete. In fact, most of the Blu-ray players coming out will support upscaling of DVDs to 1080p/1080i, so your existing DVD collection will look even better than before. While it's up to each manufacturer to decide if they want to make their products backwards compatible with DVD, the format is far too popular to not be supported. The Blu-ray Disc Association (BDA) expects every Blu-ray Disc device to be backward compatible with DVDs.



The simple answer is HDTV. If you've ever seen high-definition (HD) video on an HDTV, then you know just how incredibly sharp the picture is and how vivid the colors are. In fact, HD offers five times the amount of detail compared to standard-definition (SD). The problem with today's DVDs is that they only support SD and don't have the necessary storage capacity to satisfy the needs of HD. That's where Blu-ray comes in, it offers up to 50GB of storage capacity and enables playback, recording and rewriting of HD in all of the HD resolutions including 1080p. The format also supports high-definition audio formats and lossless audio.



In addition to the greater video and audio quality, the extra storage capacity also means there will be plenty of room for additional content and special features. This combined with the new BD-J interactivity layer adopted by Blu-ray will bring the menus, graphics and special features to a whole new level. For example, you will be able to bring up the menu system as an overlay without stopping the movie, and you could have the director of the movie on the screen explaining the shooting of a scene while the scene is playing in the background. The advanced interactivity combined with the networking features of Blu-ray will also allow content producers to support new innovative features such as downloading extras, updating content via the web, and watching live broadcasts of special events.



Thanks to the greatly enhanced HD video and audio quality as well as the advanced interactivity and networking features, Blu-ray represents a huge leap forward in the DVD viewing experience and will offer consumers an unprecedented HD experience.



Parameters

Blu-ray DVD Storage capacity 25GB (single-layer)

50GB (dual-layer)

4.7GB (single-layer)

8.5GB (dual-layer)

Laser wavelength 405nm (blue laser) 650nm (red laser) Numerical aperture (NA) 0.85 0.60 Disc diameter

Disc thickness

120mm

1.2mm

120mm

1.2mm

Protection layer

Hard coating

0.1mm

Yes

0.6mm

No

Track pitch

0.32µm

0.74µm

Data transfer rate (data)

Data transfer rate (video/audio)

36.0Mbps (1x)

54.0Mbps (1.5x)

11.08Mbps (1x)

10.08Mbps (<1x)

Video resolution (max)

Video bit rate (max)

1920×1080 (1080p)

40.0Mbps

720×480/720×576 (480i/480p/576i)

9.8Mbps

Video codecs MPEG-2

MPEG-4 AVC

SMPTE VC-1

MPEG-2

-

-

Audio codecs Linear PCM

Dolby Digital

Dolby Digital Plus

Dolby TrueHD

DTS Digital Surround

DTS-HD

Linear PCM

Dolby Digital

DTS Digital Surround

-

-

-

Interactivity

BD-J

DVD-Video







Yes, as VCRs don't support recording of HD video consumers that want to record in HD will need to upgrade their video recorders. Blu-ray recorders combined with hard drives offer a very flexible alternative for those that want to record HDTV. While HD-DVRs already allow consumers to record in HD, the amount of HDTV programming that can be recorded and archived is limited by the size of the hard drive. Blu-ray recorders will offer a solution to this problem as they allow consumers to record the video to Blu-ray discs and then free up the hard drive. This should make them popular among people that want to archive a lot of their HDTV recordings. The Blu-ray recorders will also offer a lot of compelling new features not possible with a traditional VCR:



Random access - instantly jump to any place on the disc

Searching - quickly browse and preview recorded programs in real-time

Create playlists - change the order of recorded programs and edit recorded video

Simultaneous recording and playback of video (enables Time slip/Chasing playback)

Automatically find an empty space to avoid recording over programs

Improved picture - ability to record high-definition television (HDTV)

Improved sound - ability to record surround sound (Dolby Digital, DTS, etc)





There are plans for BD-ROM (read-only), BD-R (recordable) and BD-RE (rewritable) drives for PCs, and with the support of the worlds two largest PC manufacturers, HP and Dell, it's very likely that the technology will be adopted as the next-generation optical disc format for PC data storage and replace technologies such as DVD±R, DVD±RW, and DVD-RAM.







Blu-ray movies



