Blu-ray and DVD formats

Blu-ray, DVD+R, DVD+RW, DVD-RAM, DVD-R, DVD-RW, DVD-ROM; which format is compatible with your system?

BLU-RAY
Developed by Sony, Blu-ray Disc (BD) is a next-generation optical disc format meant for storage of high-definition video and high-density data. The Blu-ray standard was jointly developed by a group of consumer electronics and PC companies called the Blu-ray Disc Association (BDA). Compared to the HD DVD format, its main competitor, Blu-ray has more information capacity per layer, 25 instead of 15 gigabytes.
Blu-ray gets its name from the shorter wavelength (405 nm) of a “blue” (technically blue-violet) laser that allows it to store substantially more data than a DVD, which has the same physical dimensions but uses a longer wavelength (650 nm) red laser.

DVD-
These formats are supported by Panasonic, Toshiba, Apple Computer, Hitachi, NEC, Pioneer, Samsung and Sharp. These formats are also supported by the DVD Forum.

DVD-R
A DVD-Recordable or DVD-R is an optical disc with a larger storage capacity than a CD-R, typically 4.7 GB (4.38 GB) instead of 700 MB, although the capacity of the original standard was 3.95 GB. Pioneer developed the 8.54 GB dual layer version, launched in 2005. A DVD-R can be written to only once, whereas a DVD-RW (DVD-rewritable) can be rewritten multiple times. The DVD-R format was developed by Pioneer in autumn of 1997. It is supported by most DVD players, and is approved by the DVD Forum.
DVD-R discs are composed of two 0.6 mm polycarbonate discs, bonded with an adhesive to each other. One contains the laser guiding groove and is coated with the recording dye and a silver, silver alloy or gold reflector. The other one (for single-sided discs) is an ungrooved “dummy” disc to assure mechanical stability of the sandwich structure, and compatibility with the compact disc standard geometry which requires a total disc thickness of about 1.2 mm. Double-sided discs have two grooved, recordable disc sides, and require the user to flip the disc to access the other side. Compared to a CD’s 1.2 mm of polycarbonate, a DVD’s laser beam only has to penetrate 0.6 mm of plastic in order to reach the dye recording layer, which allows the lens to focus the beam to a smaller spot size, which is key for writing smaller pits.
In a DVD-R, the addressing (the determination of location of the laser beam on the disc) is done with additional pits and lands (called land pre-pits) in the areas between the grooves. The groove on a DVD-R disc has a constant wobble frequency used for motor control etc.

DVD-RW
A DVD-RW is a rewritable optical disc with equal storage capacity to a DVD-R, typically 4.7 GB. The format was developed by Pioneer in November 1999 and has been approved by the DVD Forum. Unlike DVD-RAM, it is playable in about 75% of conventional DVD players.
The primary advantage of DVD-RW over DVD-R is the ability to erase and rewrite to a DVD-RW disc. According to Pioneer, DVD-RW discs may be written to about 1,000 times before needing replacement, making them comparable with the CD-RW standard. DVD-RW discs are commonly used for volatile data, such as backups or collections of files. They are also increasingly used for home DVD video recorders.
Unlike DVD-R, the DVD-RW standard has always dictated a capacity of 4.7 GB. One competing rewritable format is DVD+RW. Hybrid drives that can handle both, often labeled “DVD±RW”, are very popular since there is not yet a single standard for recordable DVDs.
The recording layer in DVD-RW and DVD+RW is not an organic dye, but a special phase change metal alloy, often GeSbTe. The alloy can be switched back and forth between a crystalline phase and an amorphous phase, changing the reflectivity, depending on the power of the laser beam. Data can thus be written, erased and re-written.

DVD+
DVD+R and DVD+RW formats are supported by Philips, Sony, Hewlett-Packard, Dell, Ricoh, Yamaha and others.

DVD+R
DVD+R is a writable optical disc with 4.7 GB (4.38 GiB) of storage capacity. The format was developed by a coalition of corporations, known as the DVD+RW Alliance, in mid 2002. Since the DVD+R format is a competing format to the DVD-R format, which is developed by the DVD Forum, it has not been approved by the DVD Forum, which claims that the DVD+R format is not an official DVD format.
In October of 2003, it was demonstrated that double layer technology could be used with a DVD+R disc to nearly double the capacity to 8.5 GB per disc. Manufacturers have incorporated this technology into commercial devices since mid-2004.
Unlike DVD+RW discs, DVD+R discs can only be written to once. Because of this, DVD+R discs are suited to applications such as nonvolatile data storage, audio, or video.
The DVD+R format is divergent from the DVD-R format. Hybrid drives that can handle both, often labeled “DVD±RW”, are very popular since there is not yet a single standard for recordable DVDs. There are a number of significant technical differences between the dash and plus formats, and although most consumers would not notice the difference, the plus format is considered by some to be better engineered.
Like other plus media, it is possible to use bitsetting to increase the compatibility of DVD+R media.

DVD+RW
A DVD+RW is a rewritable optical disc with equal storage capacity to a DVD+R, typically 4.7 GB. The format was developed by a coalition of corporations, known as the DVD+RW Alliance, in late 1997, although the standard was abandoned until 2001, when it was heavily revised and the capacity increased from 2.8 GB to 4.7 GB. Credit for developing the standard is often attributed unilaterally to Philips, one of the members of the DVD+RW Alliance. Although DVD+RW has not yet been approved by the DVD Forum, the format is too popular for manufacturers to ignore, and as such, DVD+RW discs are playable in 3/4 of today’s DVD players.
Unlike the DVD-RW format, DVD+RW was made a standard earlier than DVD+R. One competing rewritable format is DVD-RW. Hybrid drives that can handle both, often labeled “DVD±RW”, are very popular since there is not yet a single standard for recordable DVDs.
DVD+RW discs can be rewritten about 1,000 times, making them comparable with the CD-RW standard. DVD+RW discs are commonly used for volatile data, such as backups or collections of files. However, they are not as widely used for home DVD video recorders as DVD-RW, primarily because they were originally designed for storage of data, rather than of video. Of late, a number of cheaper and “no-name” manufacturers have started releasing DVD recorders using the DVD+RW format rather than DVD-RW, leaving the branded manufacturers (except Philips of course) to fly the DVD-RW flag. For computer use, the DVD-R non-rewritable variant of DVD-RW is vastly more popular than DVD+R, and mail order or bulk pricing of DVD-R media is significantly cheaper than DVD+R.
DVD+RW disks support “lossless linking”, which allows re-writing and editing of content without requiring a full erasure of the disc.
The recording layer in DVD-RW and DVD+RW is not an organic dye, but a special phase change metal alloy, often GeSbTe. The alloy can be switched back and forth between a crystalline phase and an amorphous phase, changing the reflectivity, depending on the power of the laser beam. Data can thus be written, erased and re-written.
Other DVD Formats

If you thought a DVD weas a just a DVD, think again. There are a number of different formats vying for a piece of the lucarative DVD and home entertainment market.

DVD±R
Hybrid drives that handle both formats are labeled DVD±R and Super Multi (which includes DVD-RAM support) and are very popular.

DVD-RAM
A DVD format wherein DVD-RAM discs can be recorded and erased repeatedly but are only compatible with devices manufactured by the companies that support the DVD-RAM format. DVD-RAM discs are typically housed in cartridges. DVD-R, DVD-RW and DVD-RAM are supported by Panasonic, Toshiba, Apple Computer, Hitachi, NEC, Pioneer, Samsung and Sharp. These formats are also supported by the DVD Forum.

DVD-R DL
DVD-R DL (Dual Layer) (Also Known as DVD-R9) is a derivative of the DVD-R format standard. DVD-R DL discs employ two recordable dye layers, each capable of storing nearly the 4.7 GB of a single-layer disc, almost doubling the total disc capacity to 8.54 GB. Discs can be read in many DVD devices (older units are less compatible) and can only be written using DVD±RW DL burners.
Dual layer technology is supported by a range of manufacturers including Dell, HP, Verbatim, Philips, Sony, Yamaha and others. As the name suggests, dual layer technology provides two individual recordable layers on a single-sided DVD disc. Dual Layer is more commonly called Double Layer in the consumer market, and can be seen written asor DVD-R DL.

DVD-RA
DVD-RA is used for authoring and then used for mastering DVD video or data and is not typically available to the general public.

HD-DVD
A high definition format developed by Toshiba. It has a smaller capacity than Blu-ray, but is similar to existing formats, meaning multi-compatibility might be easier to achieve. HD-DVD initially received the backing of major film studios but eventually they supported the Blu-ray format. In February 2008, Toshiba stopped making HD-DVDs.

HD-DVD-1
Taiwanese R&D organisation, Opto-Electronics & Systems Laboratories, has produced an alternative to HD-DVD and Blu-Ray, called HD-DVD-1. HD-DVD-1 is more closely related to HD-DVD than Blu-ray, with a 17GB capacity. However, there is another format (tentatively called HD-DVD-2) which has similarities to Blu-ray.

HVD
Holographic Versatile Disc (HVD) is an advanced optical disc technology still in the research stage which would greatly increase storage over Blu-ray and HD DVD optical disc systems These disks have the capacity to hold up to 3.9 terabytes of information, which is approximately 160 times the capacity of single-layer Blu-ray Discs. The HVD also has a transfer rate of 1 Gbit/s.

EVD
China’s own digital video disc format is called Enhanced Video Disc or EVD. Format uses blue-laser discs, just like AOD and Blu-Ray do, but the exact capacity is not known at the moment. The most interesting part of the disc’s specifications is in its video compression method. EVD uses proprietary video codecs developed by American On2 Technologies, called VP5 and VP6 that deliver significantly better video quality with lower bitrate levels than the MPEG-2 used in DVD-Video discs.

FVD
FVD, or Forward Versatile Disc, is an offshoot of DVD developed in Taiwan jointly by the Advanced Optical Storage Research Alliance (AOSRA) and the Industrial Technology Research Institute (ITRI) as a more inexpensive alternative for high-definition content. The disc is similar in structure to a DVD, in that pit length is the same and a red laser is used to read it, but the track width has been shortened slightly to allow the disc to have 5.4GB of storage per layer as opposed to 4.7GB for a standard DVD. The specification allows for up to three layers for total of 15GB in storage. WMV9 is used as the video codec allowing for 135 minutes of 720p video on a dual layer disc and 135 minutes of 1080i video on a 3-layer disc. FVD uses AAES copy protection which is one of the same schemes used in both HD-DVD and Blu-Ray discs. FVD is not expected to be marketed outside of Taiwan.
An FVD disc can either be a FVD-1 or FVD-2 disc: FVD-1: The coding format of the first-generation of FVD adopts 8/16 modulation codes (same as DVD). FVD-2: The second-generation will use the more efficient 8/15 coding for increasing the ECC capability (to avoid DVD patents).

Sources: DVD Forum and britlink

02/06/2010. Category: technology. Tags: , .

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