DVD Capacity
The most common discs are the DVD-5 stamped discs. They can hold 4.7 Gigabytes of information per side, which is about 133 minutes of MPEG-2 video/audio. However this varies greatly, due to the data rates of the MPEG2 video and audio streams (the amount of compression), and whether or not there are menu's, extras, chapter points, subtitles, etc.
Both CD’s and DVD’s store information in the form of engraved pits on its surface to represent the digital information ( 1's & 0's ), which is read by a laser. Only the DVD manufacturers create engraved pits (sometimes called “stamping”). PC burned DVD’s use a reflective dye and the laser “burns” the data into. However, although the processes are entirely different - the resulting storage capacity is the same.
NOTE: actually, the manufacturers “say” 4.7 GB, but they use the metric system to come up with this number, which artificially inflates the actual capacity, since most people think they are quoting a binary value. They use kilo=1000 instead of the computer kilo=1024. The actual capacity = 4,707,000,000 Bytes = 4,489 MB = 4.38 GB
DVD vs DVD-R Capacity Fiasco
In computer binary measurement, a DVD-R 2.0 or DVD-RW disc using DVD-5 Recordable media can hold only 4.38 GB !!!
Media manufacturers boost the capacity
rating of their discs by using the decimal system, where 1 kB = 1000 bytes and 1 MB = 1000 kB. This way,
they can say that their discs hold 4.7 GB.
Bytes are always given in Base10 (Decimal) !!!
In the Decimal system (Base10):
1 GB10 = 1 billion bytes = 1,000,000,000 bytes
therefore 4.7 GB10 = 4.7 x 1,000,000,000 = 4,700,000,000 bytes
In the computer, Binary system (Base2):
1 GB2 = 1024 MB2 = 1024 x 1024 kB2 = 1048576 kB2
= 1048576 kB x 1024 bytes/kB = 1,073,741,800
bytes10
1 GB2 = 1024 x
1024 x 1024 bytes10 = 1,073,741,800
bytes10
Now we have the Conversion Factors for GB going from Decimal <--> Binary:
to convert from Binary to
Decimal: 1 GB10 = 1.0737418 GB2
Decimal GB = 1.0737418 x Binary GB
to convert from Decimal
to Binary: 1 GB2 = 1/1.0737418 = .9313226 GB10
Binary GB = .9313226 x Decimal GB
We only want to see what the computer (binary) capacity of a DVD is:
Binary DVD capacity = 4,700,000,000 bytes decimal x .9313226 = 4.38 GB
So, 4.7 GB decimal = 4700000000 bytes = 4.38 GB of binary capacity.
SO THEY ARE THE SAME !! The movie producers advertise their stamped DVD capacity at 4.7 GB, in decimal format. The DVD burnable disc manufacturers advertise their DVD capacity at 4.38 GB, in binary (computer format). Each holds the same amount of data: 4,700,000,000 bytes !! Remember, bytes are always given in decimal format. It isn't until we start using kilo and giga that we have two different systems.
NOTE: the actual, exact capacity is 4,707,000,000 bytes, which is rounded off to 4.7 GB decimal or 4.38 GB binary.
|
DVD Disc Type |
Actual Capacity |
|
DVD-5 (12 cm, SS/SL) |
4.37 gig (4.70 BB) of data, over 2 hours of video |
|
DVD-9 (12 cm, SS/DL) |
7.95 gig (8.54 BB), about 4 hours |
|
DVD-10 (12 cm, DS/SL) |
8.74 gig (9.40 BB), about 4.5 hours |
|
DVD-14 (12 cm, DS/ML) |
12.32 gig (13.24 BB), about 6.5 hours |
|
DVD-18 (12 cm, DS/DL) |
15.90 gig (17.08 BB), over 8 hours |
|
DVD-1 (8 cm, SS/SL) |
1.36 gig (1.46 BB), about half an hour |
|
DVD-2 (8 cm, SS/DL) |
2.47 gig (2.66 BB), about 1.3 hours |
|
DVD-3 (8 cm, DS/SL) |
2.72 gig (2.92 BB), about 1.4 hours |
|
DVD-4 (8 cm, DS/DL) |
4.95 gig (5.32 BB), about 2.5 hours |
|
DVD-R 1.0 (12 cm, SS/SL) |
3.68 gig (3.95 BB) |
|
DVD-R 2.0 (12 cm, SS/SL) |
4.37 gig (4.70 BB); 8.75 gig for rare DS discs |
|
DVD-RW 2.0 (12 cm, SS/SL) |
4.37 gig (4.70 BB); 8.75 gig for rare DS discs |
It's very common to store information on both sides of the disc resulting in a total double sided capacity of 9.4 Gigabytes. Some movie companies make use of this facility by placing a Widescreen Transfer of the film on one side & a Standard version of the film on the other. Others throw in extras on the other side.