The second layer reading starts from the beginning of the second layer, the same physical location as the end of the first layer, and ends at the end of the second layer. When the reading of the first layer finishes (not necessarily at the end of the track), the reading is transferred to the second layer. Yet, the video data is read from the beginning of the first layer towards the end of the first layer. While in the OTP mode, the second layer is read from the outside of the disk. Sectors are sequenced from the beginning of the first layer to the end of the first layer, then the beginning of the second layer to the end of the second layer. PTP is applied to DVD-ROM whose both layers start recording at the inside diameter (ID) with the lead-in and end at the outside diameter (OD) with the lead-out. There are 2 kinds of dual-layer orientation, opposite track path (OTP) and parallel track path (PTP). Detail differences in formatting and file structure mean the “usable” data area capacity does not change by exactly this much, but for all intents, a DVD-R DL has effectively 20/11ths the capacity of a DVD-R SL, and the same holds for +R, commercially pressed, and 8 cm discs. That is accounted for the lower capacity of a single-sided dual-layer DVD at 8.5 billion bytes, versus a double-sized single-layer DVD at 9.4 billion (for 12 cm discs). One of the techs adopted to compensate for those reliability drawbacks is a 10% increase in minimum mark (digital 1 or 0) length on the drive with a corresponding 10% increase in rotation speed and a 10% reduction in gross recordable capacity. The stacked, shine-through arrangement of layers does come with a small increase in error rate due to reduce the reflectivity of the written layers, and a similar small risk of crosstalk interference. Yet, the data transfer rates of DL discs for both reading and recording are still much slower than that of SL drives. A lot of current DVD recorders support the tech of dual layer and the price of dual-layer media is now comparable to that of single layer discs, though the blank media remain more expensive. Thus, studios began listing a standard message explaining the double-layer pausing effect on all dual-layer disc packaging.ĭVD recordable (DVD-R) discs supporting this technology are backward-compatible with some existing DVD players and DVD-ROM drives.
There is a noticeable pause (up to several seconds) when the layer change happens in some DVD players, which makes many users think that their dual layer DVDs are damaged. The drive of double layer reaches the second layer by shining the laser through the first semi-transparent layer.
#Dual media player software
Double-layer DVD-R was designed by Pioneer Corporation for the DVD Forum, whereas dual-layer DVD+R was created by Philips and Mitsubishi Kagaku Media (MKM) for the DVD+RW Alliance.Īlso read: Best DVD Burning Software - Burn Image/Audio/Video to DVDĭual layer DVD discs are different from their common DVD counterpart by employing a second physical layer within the drive itself. Dual Layer Recordingĭual-layer recording enables DVD+R and DVD-R to save significantly more data, up to 8.5GB per disc, compared with 4.7 gigabytes for single-layer discs. Yet, manufacturing support for those rewritable dual-layer discs didn’t materialize to costs and expected competition from newer and higher-capacity formats such as HD DVD and Blu-ray.
In March 2006, a double-layer DVD+RW specification was approved with a capacity of 8.5 GB. In 2005 a specification for dual layer DVD-RW discs with a capacity of 8.5 GB was approved by the DVD Forum and JVC announced their development of the first media in that format. The latest DL drives write double layer DVD discs at a slower speed (up to 12x) than current single-layer discs (up to 24x). However, as of March 2011, DL drives are up to twice as expensive as single-layer media. In 2005, the dual-layer versions of DVD-R appeared on the market. What is double layer DVD? In October 2003, it was demonstrated that double-layer technology could be used with a DVD+R disc, which began to be seen in the market in the middle of 2004 with prices comparable to those existing single-layer drives. They can be read on many DVD devices with less compatibility with older ones. While DVD-R DL (DVD rewritable dual layer), also called DVD-R9, is a derivative of the DVD-R format standard.ĭVD±R dual-layer discs adopt 2 recordable dye layers with each capable of saving about 4.7 GB of data of a single-layer (SL) disc, almost doubling the total disc capacity to 8.5 GB. Dual Layer DVD±RĭVD+R DL (DVD recordable dual layer), also known as DVD+R9, is a derivative of the DVD+R format developed by the DVD+RW Alliance. To learn the meaning of a dual-layer (DL) DVD, let’s look at the definition of the DVD+R DL and DVD-R DL.
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