What is Blu-ray Disc
The Blu-ray disc (BD) has been developed to meet the demands of media rich entertainment applications and High Definition Video recording and movie distribution. A Blu-ray disc can hold between 25GB and 50GB of data which is great news for high definition movies which use far more data than can fit on a standard DVD disc.
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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)
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BD will also likely be used for data backup, archiving and retrieval. The BD disc looks, physically, just like a DVD or CD, however whereby a DVD can contain 9GB (dual layer) max, a dual layer BD can contain up to 50GB. 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 can be stored on a 50GB disc. About 23 hours of standard-definition (SD) video can fit on a 50GB disc.
The reason so much more data can be stored in this same physical space is due to the narrow wave length offered by the blue laser type used in recording Blu-ray and HD-DVD discs. The benefits afforded by the Blu-ray technology will allow for the development of rich media applications, interactive environments, HD movies and the birth of a wide range of further applications.
The latest development of the DVD format is the Blu-ray burner drive.A Blu-ray drive uses a blue laser in place of the previous red laser used for the DVD format. The blue laser has a shorter wavelength allowing much more data to be packed into a single disc.
Available Formats of BD and BD Drive: (Blu-ray Disc/ Drive)
Like a CD or DVD-ROM a BD-ROM will be a manufactured disc that is moulded and pressed and will be the distribution method of choice for HD movies, games, software etc. In addition for in-house requirements the BD-R - recordable format will be adopted for HD video recording and PC data storage and BD-RE is a re-writable format for data and video. It is also expected that a HYBRID disc featuring both Blu-ray and DVD or CD playback will be available. At this time it is not known if a hybrid disc will be cost effective.
BD-R/RE AV format:
BD-R/RE Audio Visual (BD-R/RE AV) is a format designed to record and play back full quality high (HD) and standard (SD) definition digital television broadcasts on BD-R (recordable) and BD-RE (rewritable). The BD-AV will allow consumers for example to use HD (or SD) video content in order to “author” a BD disc that will be playable in a standalone BD-player. SD material can be captured from analog sources and direct transfers from DV camcorders, allowing up to 2 hours of HD material to be stored on a 25 GB single-layer.
BD-ROM AV format:
BD-ROM Audio Visual (BD-ROM AV) is an application format designed to meet the requirements of the film industry for distributing high definition (HD) commercial movies on BD-ROM (prerecorded). It combines the features offered by DVD in addition to support for HD video, multi channel audio and enhanced interactive and network features.
What Audio Codecs Will Blu-ray Support?
Linear PCM(LPCM) – upto 8 channels of uncompressed audio.(mandatory)
Doby 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.
Video codecs Blu-ray support:
01/ MPEG-2 - enhanced for HD, also used for playback of DVDs and HDTV recordings. 02/ MPEG-4 AVC - part of the MPEG-4 standard also known as H.264 (High Profile and Main Profile). 03/ SMPTE VC-1 - standard based on Microsoft’s Windows Media Video (WMV) technology.
How Does BD Works:
It Works much the same way as CD or DVD optical disc drive does by using a thin plastic disc which has a very fine spiral track with dips and bumps running along it.
The disc has an aluminium backing on the top side and the drive uses a laser and receiving optics to read the bottom surface with the spiral track by bouncing the beam from the laser off of the reflective layer of the disc formed by the metal coating on the far side of the disc behind the spiral track.
When the laser hits a dip the light is reflected back and when it hits a bump no light is reflected back and so a digital 1 0 1 0… etc data pattern is formed by the dips and bumps along the spiral track.
The dips and bumps are either created by being stamped or pressed at a factory or by a laser within your PCs optical burner drive when you ‘burn’ your own disc for data storage.
The disc is spun with a motor assembly and the laser and associated lens, used to read the reflected light, is tracked along the spiral track using a precision tracking mechanism allowing the laser to read the data as it travels along the spiral.
The difference between your DVD drive and your Blu-ray drive is purely down to the use of a blue laser with a shorter wavelength than the red laser used in your DVD drive.
This shorter wavelength gives the laser a more accurate focusing of its beam so that more information can be packed into the same diameter size disc - around 25GB per layer – much improved upon over a standard DVD with only 4.7GB per layer!
The intention is that Blu-ray will progress along the lines of multiple layers and eventual storage space may increase up to 100GB per disc and beyond!
Blu-ray burner?
If you are building or buying a new PC or maybe replacing your PCs optical drive you will want to look at adding a Blu Ray burner or Blu-ray drive.
Why? Well it makes sense to go for the new format Blu-ray drive as thy are in general backward compatible with the older DVD format and can burn and read your old DVDs happily whilst giving you the benefits of HD (High definition).
If you already own a HD television you will be able to use your Blu-ray burner drive to burn HD quality films and video which you will be able to watch in High definition on your stand alone Blu-ray player or, if you have one, using Sony’s Playstation 3 which has a Blu-ray drive built into it!
Check the supported formats when purchasing a drive or burner making sure it supports the DVD write and read formats you should require.
There are a multitude of Blu-ray drives available for your PC now.
Blu-ray Drive Burning Speed
Burning speeds are still quite slow in comparison to DVD optical drives but they are fast improving all the time, up to 8x at the time of writing.
A Blu Ray burner will be able to write to discs, assuming suitable media of course, in the times indicated below:
Drive Speed Data Rate Write Time
1 x 36Mbits/s 90 minutes2 x 72Mbits/s 45 minutes4 x 144Mbits/s 23 minutes6 x 216Mbits/s 15 minutes8 x 288Mbits/s 12 minutes
The above times are for single layer discs, dual layer discs will take twice as long.
Time is for a complete disc write, i.e. 25GB.
What will you need to go Blu-ray?
If you are considering adding a Blu Ray drive to your PC you will need to ensure that your processor, graphics card and monitor are up to the required specification.
You will need an HD compatible monitor and a graphics card with enough processing power and the correct outputs to suit.
Sufficient research here is essential before buying.
Adding a Blu-ray burner to your PC rather than buying a dedicated player does give you a lot more options over simply playing bought or rented Blu Ray films.
There are many sources of downloadable HD content such as Apple iTunes etc and a Blu-ray burner in your PC would give you many more options and also allow you to connect your PC direct to your HD capable TV should you so wish.
Hey, what about home video fanatics? HD video recorders or camcorders are now becoming available and a Blu Ray burner would be a bonus here too.
Blu Ray Media and Software
DVD blank media are easy to come by but Blu-ray blank discs are still thin on the ground.
Look for BD-R and BD-R DL (Dual layer) quad or greater speed discs.
You will also need some software to allow you to burn to your Blu-ray drive.
Nero 7 Essentials will do the job nicely.
Will Blu-ray support mandatory managed copy?
Mandatory managed copy (MMC) will be part of the Blu-ray format, allowing consumers to make legal copies of their Blu-ray movies for local use. This function is subject to hardware support from manufacturers.
How effective is the BD Copy Protection?
BD movie discs use Advanced Access Content System (AACS) to help prevent un-authorised copying, however the effectiveness is jeopardised since most TV’s or monitors do not support HDCP. Since there is no high bandwidth copyright protection in place copies can be made via analog connections.
What to look for when selecting a Blu Ray Burner
Look for a large buffer memory to ensure smooth transfer of data and if you are going to be doing backups or video encoding regularly then you will need to look carefully at the speed for writing to blank discs for a Blu-ray burner drive.
If you are also going to be using DVDs then look at the drives capability for reading and writing to DVD and which formats it supports.
Don’t worry too much, as long as the drive supports DVD+R and DVD-R you should be fine.
Internal or External Blu-ray Drive?
Your choice here, if you don’t mind delving within the inner workings of your PC go for the internal drive.
It will be faster, cheaper and one less thing to clutter up your desk.
An external drive however can be easily connected via USB 2.0 or Firewire ports and will be operational immediately.
The downside to this is that portable external drives are generally a bit slower at burning disks than their internal optical drive counterparts.
The upside ? Well apart from the simplicity of connection, they are also portable and can be switched between laptops and desktop PCs etc with ease.
Don’t forget though, the external drive will be yet another piece of equipment to clutter up your desk!
Is Blu-ray the same thing as HD-DVD?
HD-DVD is a competing next-generation optical disc format developed by Toshiba and NEC. Although the format uses the same principle of blue laser technology it is quite different from Blu-ray.
Are BD devices compatible with CDs and DVDs?
The BD specifications do not dictate backwards compatability. It is up to manufacturers to consider this requirement and build in compatability as required.
Blu-ray Vs. DVD
Will Blu-ray replace DVDs?
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.
Will Blu-ray be backwards compatible with DVD?
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.
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Parameters
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Blu-ray
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DVD
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Storage capacity
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25GB (single-layer)
50GB (dual-layer)
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4.7GB (single-layer)
8.5GB (dual-layer)
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Laser wavelength
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405nm (blue laser)
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650nm (red laser)
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Numerical aperture (NA)
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0.85
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0.60
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Disc diameter
Disc thickness
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120mm
1.2mm
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120mm
1.2mm
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Protection layer
Hard coating
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0.1mm
Yes
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0.6mm
No
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Numerical aperture (NA)
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0.85
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0.60
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Disc diameter
Disc thickness
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120mm
1.2mm
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120mm
1.2mm
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Track pitch
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0.32µm
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0.74µm
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Data transfer rate (data)
Data transfer rate (video/audio)
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36.0Mbps (1x)
54.0Mbps (1.5x)
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11.08Mbps (1x)
10.08Mbps (<1x)
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Track pitch
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0.32µm
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0.74µm
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Video resolution (max)
Video bit rate (max)
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1920×1080 (1080p)
40.0Mbps
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720×480/720×576 (480i/576i)
9.8Mbps
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Video codecs
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MPEG-2
MPEG-4 AVC
SMPTE VC-1
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MPEG-2
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Audio codecs
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Linear PCM
Dolby Digital
Dolby Digital Plus
Dolby TrueHD
DTS Digital Surround
DTS-HD
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Linear PCM
Dolby Digital
DTS Digital Surround
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Interactivity
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BD-J
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DVD-Video
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