Active Oldest Votes. Improve this answer. Community Bot 1. This information is really interesting and useful. Xavierjazz Xavierjazz 8, 13 13 gold badges 66 66 silver badges 94 94 bronze badges. An old but very informative article. That article is highly relevant, but please avoid link-only answers. Read the dates. Read Wikipedia link for a simple explanation: Recordable format compatibility DVD drives from should be able to read either of the competing recordable formats, older drives may favour DVD-R discs.
Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password. Immediately following the formal adoption of a unified standard for DVD, two of the four leading video game console companies Sega and The 3DO Company said they already had plans to design a gaming console with DVDs as the source medium.
Contemporary games for Windows were also distributed on DVD. Some specifications for mechanical, physical and optical characteristics of DVD optical discs can be downloaded as freely available standards from the ISO website. Some DVD specifications e. HP initially developed recordable DVD media from the need to store data for backup and transport. Most DVD readers and players play both kinds of discs, though older models can have trouble with the "plus" variants.
The MID contains data such as the manufacturer and model, byte capacity, allowed data rates also known as speed , etc.. When played, a slight transition can sometimes be seen in the playback when the player changes layers. A dual-layer disc differs from its single layered counterpart by employing a second physical layer within the disc itself. The drive with dual-layer capability accesses the second layer by shining the laser through the first semitransparent layer.
In some DVD players, the layer change can exhibit a noticeable pause, up to several seconds. The recording speeds reached by dual-layer media are still well below those of single-layer media. Track 1 then starts at the outside diameter. DVD video discs are mastered slightly differently. The video is divided between the layers such that layer 1 can be made to start at the same diameter that layer 0 finishes.
This speeds up the transition as the layer changes because although the laser does have to refocus on layer 1, it does not have to skip across the disc to find it. The basic types of DVD 12 cm diameter, single-sided or homogeneous double-sided are referred to by a rough approximation of their capacity in gigabytes. In draft versions of the specification, DVD-5 indeed held five gigabytes, but some parameters were changed later on as explained above, so the capacity decreased.
Other formats , those with 8 cm diameter and hybrid variants, acquired similar numeric names with even larger deviation. These are the same sizes as a standard CD and a mini-CD , respectively. Each DVD sector contains 2, bytes of data, 2, bytes of which are user data.
Scan of a DVD-R; the "a" portion has been recorded on while the "b" portion has not. All three common optical disc media Compact disc , DVD, and Blu-ray use light from laser diodes , for its spectral purity and ability to be focused precisely. DVD uses light of nm wavelength red , as opposed to nm far-red , commonly called infrared for CD. This shorter wavelength allows a smaller pit on the media surface compared to CDs 0. In comparison, Blu-ray Disc , the successor to the DVD format, uses a wavelength of nm violet , and one dual-layer disc has a 50 GB storage capacity.
DVD-Video became the dominant form of home video distribution in Japan when it first went on sale in , but it shared the market for home video distribution in the United States until June 15, , when weekly DVD-Video in the United States rentals began outnumbering weekly VHS cassette rentals. CSS utilizes a proprietary bit stream cipher algorithm. The system was introduced around and was first compromised in The rise of filesharing has prompted many copyright holders to display notices on DVD packaging or displayed on screen when the content is played that warn consumers of the illegality of certain uses of the DVD.
It is commonplace to include a second advertisement warning that most forms of copying the contents are illegal. Many DVDs prevent skipping past or fast-forwarding through this warning. Arrangements for renting and lending differ by geography. In the U. It can also be copied and retrieved. It is the pioneer optical storage disc, which totally changes the storage concept and make way for more advanced mediums and discs such as DVD. The compact disc is best for storing less capacity of data.
CD-R can store up to megabytes of data. The best thing about CD-R is that it can be played by the drives that are not specifically are for CD. Harlon currently works as a quality moderator and content writer for Difference Wiki. He graduated from the University of California in with a degree in Computer Science. Follow him on Twitter HarlonMoss. Harlon Moss.
Updated: February 27, This is also known as bitsetting. As RAM stands for Random Access Memory, it works more or less like a hard-drive and was designed for corporate back-up use. Currently available in standard 4. DVD Forum backs this format. It uses physical dedicated sector markers visible as rectangles on the read side of the disc instead of the pre-pits or wobbles used in other types of recordable and rewritable media.
Multi-format drives can read and write more than one format; e. DVD recordable media are sold in two standard sizes, a regular 12 cm size for home recording and computer usage, and a small 8 cm size sometimes known as a miniDVD for use in compact camcorders. The following table describes the maximal speed of DVD-R and the relative typical write time for a full disc according to the reviews from cdrinfo.
Many reviews of multiple brand names on varying conditions of hardware and DVD give much lower and wider measurements than the optimal numbers below. The table below largely assumes CAV. Library of Congress, most recordable CD products have a higher probability of greater longevity compared to recordable DVD products.
Media of higher quality tends to last longer. Using surface error scanning, the rate of correctable errors can be measured. Not all optical drive models are able to scan the disc quality. DVD-R discs are composed of two 0. One contains the laser guiding groove and is coated with the recording dye and a 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.
The sandwich structure also helps protect the layer containing data from scratches with a thick "dummy" disc, a problem with CDs, which lack that structure. 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. 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 of In , JVC announced an archival DVD recording medium manufactured with quality control and inspection frequencies techniques greater than is traditionally used in media manufacturing, and using specially developed silver alloy as a reflective layer and organic dye with in-house developed additives to secure long-term data retention.
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.
0コメント