General Answers About Blu-ray
What is Blu-ray?
Blu-ray is also known as Blu-ray Disc (BD). It is the name of a next-generation optical disc format. The Blu-ray format was developed to enable recording, rewriting and playback of high-definition video (HD), and is also capable of storing large amounts of data. The format provides more than five times the storage capacity of traditional DVDs, ranging from 25GB on a single-layer disc to 50GB on a dual-layer disc.
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Why is it named Blu-ray?
The name Blu-ray originates from the core technology, which employs a blue-violet laser that reads and writes data. The name is a combination of "Blue", for the blue-violet laser, and "Ray", for the optical ray. The Blu-ray Disc Association states that the spelling of "Blu-ray" is not a mistake, and that the letter "e" was intentionally left out so that the name could be registered as a trademark.
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Who created Blu-ray?
The Blu-ray Disc format was created by the Blu-ray Disc Association> (BDA), a group of the foremost consumer electronics, computer hardware, and motion picture production companies, with more than 180 members from around the globe. The current Board of Directors 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
- Thomson Multimedia
- Twentieth Century Fox
- Walt Disney Pictures
- Warner Bros. Entertainment
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What Blu-ray formats will be available?
As with conventional CDs and DVDs, Blu-ray plans to include a broad range of formats from Read Only Memory (ROM) to Record Only (R) and Rewritable (RW). The following formats are part of the Blu-ray Disc classification:
- BD-ROM - read-only format: primarily used for the distribution of HD movies, games, software, etc
- BD-R - recordable format: primarily used for HD video recording and PC data storage.
- BD-RE - rewritable format: primarily used for HD video recording and PC data storage.
Plans are also in the works for a BD/DVD hybrid format, which will combines both Blu-ray and DVD on the same disc enabling it to be played in both Blu-ray players and DVD players.
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How much data can a Blu-ray disc hold?
A single-layer disc will be able to hold 25GB and a dual-layer disc will be able to hold 50GB.
To establish itself for the future, the Blu-ray Disc format is easily extendable and includes support for multi-layered discs, which would allow the storage capacity to be increased to 100GB-200GB (25GB per layer) simply by adding more layers to the discs.
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How many hours of video can a Blu-ray disc hold?
A 50GB disc can hold over 9 hours of high-definition (HD) video or about 23 hours of standard-definition (SD) video.
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How fast can data be read from or written to a Blu-ray disc?
1x speed is defined as 36 Mbps, according to the Blu-ray Disc specs. BD-ROM movies will require a 54Mbps data transfer rate, so its safe to expect the minimum speed to be 2x (72Mbps). Due to the larger numerical aperture (NA) adopted by Blu-ray Disc, Blu-ray has the potential for much higher speeds. The larger NA value will require less recording power and lower disc rotation speed than DVD and HD-DVD to achieve the same data transfer rate. In the past, the media itself limited the recording speed. However, the only limiting factor for Blu-ray is the capabilty of the hardware involved. With a maximum disc rotation speed of 10,000 RPM at the outer diameter, a speed of 12x (about 400Mbps) could be possible. Thus, the Blu-ray Disc Association (BDA) currently has plans to raise the speed to 8x (288Mbps) or possibly more in the future.
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Which video codecs will be supported by Blu-ray?
MPEG-2 - HD enhanced, provides for playback of DVDs and HDTV recordings.
MPEG-4 AVC - referred to as H.264, it is part of the MPEG-4 standard (High Profile and Main Profile).
SMPTE VC-1 - standard based on Microsoft's Windows Media Video (WMV) technology.
Note that all Blu-ray players and recorders will be required to support playback of all three video codecs. It will still remain in the movie studios' hands to determine which video codec(s) they will use for their releases.
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Which audio codecs will be supported by Blu-ray?
- Linear PCM (LPCM) - provides up to 8 channels of uncompressed audio. (mandatory)
- Dolby Digital (DD) - current format used for DVDs, 5.1-channel surround sound. (mandatory)
- DTS Digital Surround - current 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-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)
Note that all Blu-ray players and recorders will be required to support playback of LPCM, DD and DD+. Players have the option to support any of the other codecs. It will still remain in the movie studios' hands to decide which audio codec(s) they use for their releases.
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Will a cartridge be required for Blu-ray discs?
No, cartridges have been made obsolete with the development of new low cost hard-coating technologies. Blu-ray will entrust its protection on hard-coating, which when applied, will make the discs even more scratch and fingerprint resistant than even today's DVDs, without affecting the look and feel of the disc. A new error correction system, in use by Blue-ray, is more capable and effective than the one used for DVDs.
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Will an Internet connection be required for Blu-ray?
No, an Internet connection is not required for the playback of Blu-ray movies. A connection might only be needed for extra features, watching recent movie trailers, web browsing, etc. When transferring managed copies of Blu-ray movies over a home network, it will be required for authoring.
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Will Blu-ray downconvert the analog output signal?
No. Blu-ray players will not downconvert the analog output signal to a lower definition unless the video contains an Image Constraint Token or ICT. This feature is not part of the Blu-ray Disc design, but is instead part of the AACS copy-protection system also equipped by HD-DVD. It will, however, be up to each movie studio to make the choice of whether they want to use an ICT on their releases or not. So far, Sony, Disney, Fox, Paramount, MGM and Universal have already stated that they do not plan on using this feature. Other studios, which haven't made the decision, will most likely make the same choice to avoid any bad publicity. If any of the studios do make the decision to use ICT they will be required to state so on the cover of their movies.
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Will Blu-ray allow for mandatory managed copy?
Yes. Mandatory managed copy (MMC) will be a required part of the Blu-ray formatting. MMC will permit consumers to make legal copies of their Blu-ray movies that will then be transferable over a their home network. Note however, that "mandatory" refers only to the movies having to offer this capability, whereas each hardware manufacturer will decide if they want to support this feature.
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When will Blu-ray products be available for me the purchase?
Blu-ray players from Samsung, Panasonic, Sony, Philips and Pioneer are already available in U.S. and Canadian stores. A growing selection of Blu-ray moviesis also available in these stores. LG and Sharp are also expected to produce Blu-ray players and Samsung is planning to introduce a second-generation Blu-ray player in the near future. European countries should now also have access to the first Blu-ray hardware and software.
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What will be the cost of Blu-ray products?
As with most new technologies, the first generation of products is typically quite expensive due to the low production volumes. This shouldn't be a problem much longer as there is a wide range of Blu-ray related products from players and recorders to drives, writers and media that are planned, which will help to drive up production volumes and lower the overall production costs. Once the overall mass production of components for Blu-ray products begins, the prices are sure to fall abruptly.
The Blu-ray Disc Association has stated that the overall cost of manufacturing Blu-ray Disc media will in the end be equal to that of producing a DVD. The reduced injection molding costs (one molding machine rather than two, no birefringence problems) compensate for the additional cost of applying the cover layer and low cost hard-coat, while the techniques used for applying the recording layer remain unchanged. As a result of increased production volumes, production costs will ultimately fall and be comparable to DVDs. Back To Questions
Blu-ray Disc and DVD
Will DVDs be replaced by Blue-ray?
Yes, that's the belief. The major movie studios support the Blu-ray format as a successor to today's DVD format. Seven of the eight major movie studios (Disney, Fox, Warner, Paramount, Sony, Lionsgate and MGM) have already released titles in the Blu-ray format. Most studios have also announced that they will begin releasing new feature films concurrently on Blu-ray Disc and DVD, as well as a continuous slate of catalog titles every month.
It should be noted that the two formats (Blu-ray and DVD) will most likely co-exist for quite some time until HDTVs are more widely used. Back To Questions
Will Blu-ray be backwards compatible with DVD?
Yes, several leading consumer electronics companies such as Sony, Panasonic, Philips, Samsung, Pioneer, Sharp and LG have already developed products that can read/write CDs, DVDs and Blu-ray discs using a BD/DVD/CD compatible optical head, so existing DVD collections will not become obsolete. Actually, most Blu-ray players being released will upscale DVDs to 1080p/1080i, so existing DVD collections will in fact, be improved. Though in the hands of each manufacturer to determine if they want to make their products backwards compatible with DVD, the format too prevalent to not be supported. The Blu-ray Disc Association (BDA) expects every Blu-ray Disc device to be backward compatible with DVDs.
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Why should I upgrade from DVD to Blu-ray?
In short, HDTV. High-definition (HD) video on an HDTV provides an incredibly sharp picture with immensely vivid colors. HD offers five times more detail compared to standard-definition (SD). The dilemma with today's DVDs is that they only support SD and lack the storage capacity to satisfy the needs of HD. It is here that Blu-ray's strength shines. Blu-ray offers up to 50GB of storage capacity and enables playback, recording and rewriting of HD in all of the HD resolutions including 1080p. It also supports high-definition audio formats and lossless audio formats.
Along with the superior video and audio quality, the extra storage capacity provides plenty of room for additional content and special features. Coupled with the new BD-J interactivity layer adopted by Blu-ray, the menus, graphics and special features will be brought to a whole new level. One example is that 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. When combined with the advanced interactivity, the networking features of Blu-ray will allow content producers to provide new innovative features such as downloading extras, updating content via the web, and watching live broadcasts of special events. With these advanced features, Blu-ray represents a huge leap forward in the DVD viewing experience. Back To Questions
What is the difference between Blu-ray and DVD?
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/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
|
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Will VCRs be replaced by Blu-ray?
Yes, VCRs don't support recording of HD signals, thus consumers will soon need to replace them. Blu-ray recorders coupled with hard drives oprovide a versatile alternative for those that want to record HDTV. Though HD-DVRs already allow consumers to record HDTV, the size of the hard drive limits the amount of HDTV programming that can be recorded and archived. However, Blu-ray recorders will allow consumers to record the video to Blu-ray discs and freeing up the hard drive. The Blu-ray recorders will also offer a lot of compelling new features not possible with a traditional VCR recordings:
- Random access - provides the ability to skip to any place on the disc
- Searching - quickly browse and preview recorded programs
- 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
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Will Blu-ray be avalable for PCs?
There are plans for BD-ROM (read-only), BD-R (recordable) and BD-RE (rewritable) drives for PCs. With the added support of the worlds two largest PC manufacturers, HP and Dell, it's very probable that the technology will step up as the next-generation optical disc format for PC data storage and replace technologies such as DVD±R, DVD±RW, and DVD-RAM.
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Blu-ray and HD-DVD
Are Blu-ray and HD-DVD the same?
No, HD-DVD (previously known as AOD) is the name of a competing next-generation optical disc format developed by Toshiba and NEC. The format is varies from Blu-ray, but does however rely heavily on blue-laser technology to achieve a higher storage capacity. The format is being developed within the DVD Forum as a possible successor to the current DVD technology.
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What benefits does Blu-ray provide over HD-DVD?
Though similar in many ways, there are some important differences between Blu-ray and HD-DVD.
First off is the capacity. Because Blu-ray employs a lens with a greater numerical aperture (NA) than HD-DVD, the laser spot can be focused with greater precision to fit more data on the same size disc. This allows Blu-ray to hold 25GB per layer (50GB on a dual-layer disc), compared to HD-DVD which can only hold 15GB per layer (30GB on a dual-layer disc). Blu-ray has also adopted a higher data transfer rate for video and audio, 54Mbps vs HD-DVD's 36.55Mbps. The greater capacity and data transfer rates for Blu-ray will enable the movie studios to release their movies with superior quality for both video and audio.
Secondly is the content. The Blu-ray format has received overwhelming support from the major movie studios as a successor to today's DVD format. Warner, Paramount, Fox, Disney, Sony, MGM and Lionsgate have all released titles for Blu-ray, whereas only Paramount and Universal have released titles for HD-DVD.
Finally is hardware support. The Blu-ray format has tremendous support from the world's leading consumer electronics, personal computer and media manufacturers, such as Sony, Panasonic, Philips, Samsung, Pioneer, Sharp, JVC, Hitachi, Mitsubishi, TDK, Thomson, LG, Apple, HP and Dell. The Blu-ray format is also supported by the next-generation PlayStation 3 (PS3) video game console. The HD-DVD format is vastly limited in its supporters, so the amount of players and hardware will be scarce. Back To Questions
What is the difference between Blu-ray and HD-DVD?
Parameters
|
Blu-ray |
HD-DVD |
| Storage capacity |
25GB (single-layer)
50GB (dual-layer)
|
15GB (single-layer)
30GB (dual-layer)
|
| Laser wavelength |
405nm (blue laser) |
405nm (blue laser) |
| Numerical aperture (NA) |
0.85 |
0.65 |
Disc diameter
Disc thickness
|
120mm
1.2mm
|
120mm
1.2mm
|
Protection layer
Hard coating
|
0.1mm
Yes
|
0.6mm
No
|
Track pitch
|
0.32µm |
0.40µm |
Data transfer rate (data)
Data transfer rate (video/audio)
|
36.0Mbps (1x)
54.0Mbps (1.5x)
|
36.55Mbps (1x)
36.55Mbps (1x)
|
Video resolution (max)
Video bit rate (max)
|
1920×1080 (1080p)
40.0Mbps
|
1920×1080 (1080p)
28.0Mbps
|
| Video codecs |
MPEG-2
MPEG-4 AVC
SMPTE VC-1
|
MPEG-2
MPEG-4 AVC
SMPTE VC-1
|
| Audio codecs |
Linear PCM
Dolby Digital
Dolby Digital Plus
Dolby TrueHD
DTS Digital Surround
DTS-HD
|
Linear PCM
Dolby Digital
Dolby Digital Plus
Dolby TrueHD
DTS Digital Surround
DTS-HD
|
Interactivity
|
BD-J
|
HDi
|
|
|
