The positioning of the DVD
To become a six-fold approximately scheme recording and reading and shape of the medium about the same and CD (compact disc), but storage capacity is much larger for the CD, and when compared with 12cm normal for a long time it was not possible with CD that the recording of the video can be is a feature. In the development, is the fact that "in the high image quality and high sound quality over the current media, and Duration of 133 minutes or more one-sided per sheet" with the aim of [in the request from the Hollywood movie industry, the recording capacity per one because of the connection with the state of the art at that time, I was developed as a disk (in the case of Single Layer) 4.7GB it becomes possible to recording 113 minutes in image quality comparable to VHS video tape method.
Video tape of conventional (such as VHS) so that was the case, it has been positioned in the major media of the video recording, movies and documentaries, such as drama, various video software are commercially available. In addition, it becomes possible to with the spread of such non-linear editing compatible PC and consumer camcorders, and save to a DVD video editing was voluntary.
Has been established by the DVD Forum (write multiple times possible) is DVD-RW, DVD-RAM (write only once) DVD-R as a recordable DVD standard. As opposed to this, there is a DVD + RW and DVD + R that developed the DVD + RW Alliance. Note that for each disk, I referred to in detail in the type of DVD.
For recordable DVD, there may be serious problems in quality to those of the foreign manufacturers part . Can cause problems block noise from entering the playback of the video, playback stops, the data that was saved disappears, the life of the recorder drive or shrink and is high disk poor quality.
However, (there is that it has adopted a foreign-made media in the country brand) because sometimes writing quality is reduced by the compatibility and performance of the drive, there is no guarantee that all right if you use the domestic media unconditionally. To use it with confidence, that it writes test to buy one piece of media you want to use from now on, to use that to ensure that there are no problems is desirable.
It is also writing media durability was said to have about 100 years originally released, but instead of testing for 100 years (actually accelerated test of good quality only media, this is changing and irradiation intensity of ultraviolet rays instead a result in those) to the environment of the 100-year equivalent Te, disk bad-quality data will be lost in a few years also exist in reality. In order to prolong the life, avoiding the place and humid place in the UV is important. In addition, there is no worry that failure tape is tangled in comparison with the VHS, but there is a possibility that become unreadable disk is damaged, it is necessary to pay attention to storage.
In a DVD, a disc that aims at recording a large capacity, so that it can be recorded on the surface to hit the label surface in the CD, the standard double-sided recording is present. However, it's flipped to when reading of one side has finished as laser disk time-consuming. Therefore, by setting to have a two-layer structure on one side, it is possible to secure more space than a single layer structure, the flip effort is eliminated. DVD + R DL recording of user type appeared in the market in June 2004, DVD-R DL is May 2005. Depending on the optical drive, there are also those that do not read the specifications and compatibility. Also, if you do not care in handling of the label surface compared to the system more, and suffer troubles such as the recording layer may be damaged as the CD.
For two-layer structure, loading of the layer in the back can not be brought to have two layers of the total reflection. Therefore, it is made of a thin metal film is the first layer on one side of the (two-sided) two-layer disc (called or "Layer 0" and "L0"), (referred to as or "Layer 1" and "L1") the second layer and has a structure to the total reflection. Reading detection rate is poor because the layer 0 is a thin film, but has an improved read performance by reducing the recording density. Therefore, two-layer disc does not have the capacity of twice the disk further.