| Q: |
How long does it take to copy a DVD recordable? |
| A: |
We use drives with a range of speeds, so if we assume a completely full disc:
| 1X |
= |
about 58 minutes |
| 2X |
= |
about 29 minutes |
| 4X |
= |
about 14 minutes |
| 8X |
= |
about 9 minutes |
| 16X |
= |
about 6 minutes |
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| Q: |
How many CDs fit onto a DVD+/-R? |
| A: |
You can fit the contents of just under 7 full (700MB) CDs onto a single layer recordable DVD (4.7GB) |
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|
| Q: |
Why does the sound of my DVD drive keep changing? |
| A: |
There are a couple of reasons:
1) If the drive has trouble reading the disc (eg. fingerprints, scratches), it will slow down the disc rotation to give the laser a better chance to read the data correctly.
2) Depending upon the age and speed of the drive, different technology is used to transfer data to and from the discs. Older drives use something called Constant Linear Velocity (CLV) which changes the rotational speed of the drive, making it faster the closer
to the centre hole the laser gets. This is to make sure that the data is being transferred via the laser at a constant bit rate. Mid-speed drives tend use Constant Angular Velocity (CAV) which rotates the disc at a constant speed no matter where on the disc surface
the data is. The newest high speed drives tend to use a combination of both methods, called Partial Constant Angular Velocity (PCAV). You are more likely to notice the change in sound (and velocity) when reading from the disc as the laser has to skip around looking
for different files. |
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|
| Q: |
Why does a DVD 'feel' more robust than a CD? |
| A: |
DVDs are manufactured using 2 discs (each about half the thickness of a CD) which are bonded together. So, unlike a CD which is made from a single piece of polycarbonate, DVDs are made by 'laminating' 2 pieces of polycarbonate together, making the disc feel
more rigid. |
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|
| Q: |
What is a 'DVD-9'? |
| A: |
DVD-9 is the most common of the 4 DVD formats, and it refers to how the discs are manufactured, and more importantly for the consumer, how they are used. Below is a simple summary of the differences:
|
>
|
DVD-5 |
The simplest of the DVD family with a capacity of 4.7GB. Of the two layers, only one contains data |
|
>
|
DVD-9 |
The most popular form of DVD (most of your movie DVDs will be DVD-9), both of the layers contain data, up to a combined maximum of 8.5GB, and both layers are read by the player from the same side |
|
>
|
DVD-10 |
With a capacity of 9.4GB (slightly higher than a DVD-9) both layers contain data, but they are bonded together in such a way that the disc needs to be turned over to read the second side, so not very popular |
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>
|
DVD-18 |
Although the capacity is just over 17GB, the technical difficulties involved in manufacturing this format mean they are rare, and very few pressing companies will make them due to the very low yield. This disc has 4 'layers', 2 readable from one side and
two readable from the other, once the disc is flipped over |
When it comes to layers with Recordable DVD there are 2 types - single-layer and dual-layer, which equate to the DVD-5 and DVD-9 formats respectively. |
| |
|
| Q: |
How do you print onto a DVD? |
| A: |
By the same methods we employ for
CD: thermal
transfer, inkjet
print, high-speed
digital, screen
print and offset
print. |
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|
| Q: |
What is the difference between DVD + (plus) and - (minus) R? |
| A: |
Not that much really! This is a little like the fight between Betamax and VHS video cassettes in the 1980s, although with +R and -R the discs are at least the same size. When writing these discs, you must have the right media to match the type of writer, so
if you have a DVD+R drive you must use DVD+R discs, and vice-versa. DVD-R, supported by the DVDForum, was the first recordable DVD format introduced and gained a stronghold in the PC and Mac computer environment. DVD+R, supported by the DVD+RW Alliance, came along
a couple of years later because of flexibility and compatibility issues between DVD-R and existing DVD home entertainment players. DVD+R was designed to be 'more compatible' with the existing DVD Video standard and therefore would have no problems with the wide
installed base of home players. As time goes on the compatibility issues between these formats reduces as new devices support both types. Essentially, once a DVD-R or DVD+R is burned, it 'should' become a standard DVD and be readable in any DVD drive.
** This FAQ was found and used in the Daily Mail 27-03-2006 ** |
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| Q: |
At what point do I get my DVDs pressed rather than duplicated? |
| A: |
Usually when you require upwards of 1000 discs - although this is only a guideline. See Duplication -v- Replication for a more comprehensive answer. |
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