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heres some info for you:
Capacities of DVD:
For reference, a CD-ROM holds about 650 megabytes, which is 0.64 gigabytes or 0.68 billion bytes. In the list below, SS/DS means single-sided/double-sided, SL/DL/ML means single-layer/dual-layer/mixed-layer (mixed means single layer on one side, dual layer on the other side), gig means gigabytes (2^30), BB means billions of bytes (10^9). See note about giga vs. billion in section 7.2.
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)
DVD-R 2.0 (12 cm, DS/SL) 8.75 gig (9.40 BB)
DVD-RW 2.0 (12 cm, SS/SL) 4.37 gig (4.70 BB)
DVD-RW 2.0 (12 cm, DS/SL) 8.75 gig (9.40 BB)
DVD+R 2.0 (12 cm, SS/SL) 4.37 gig (4.70 BB)
DVD+R 2.0 (12 cm, DS/SL) 8.75 gig (9.40 BB)
DVD+RW 2.0 (12 cm, SS/SL) 4.37 gig (4.70 BB)
DVD+RW 2.0 (12 cm, DS/SL) 8.75 gig (9.40 BB)
DVD-RAM 1.0 (12 cm, SS/SL) 2.40 gig (2.58 BB)
DVD-RAM 1.0 (12 cm, DS/SL) 4.80 gig (5.16 BB)
DVD-RAM 2.0 (12 cm, SS/SL) 4.37 gig (4.70 BB)*
DVD-RAM 2.0 (12 cm, DS/SL) 8.75 gig (9.40 BB)*
DVD-RAM 2.0 (8 cm, SS/SL) 1.36 gig (1.46 BB)*
DVD-RAM 2.0 (8 cm, DS/SL) 2.47 gig (2.65 BB)*
CD-ROM (12 cm, SS/SL, 74 minutes) 0.635 gig (0.682 BB)
CD-ROM (12 cm, SS/SL, 80 minutes) 0.687 gig (0.737 BB)
CD-ROM (8 cm, SS/SL) 0.180 gig (0.194 BB)
DDCD-ROM (12 cm, SS/SL) 1.270 gig (1.364 BB)
DDCD-ROM (8 cm, SS/SL) 0.360 gig (0.387 BB)
* Formatted DVD-RAM discs have slightly less than stated capacity. For example, the contents of a completely full DVD-R will not quite fit on a DVD-RAM.
Tip: It takes about two gigabytes to store one hour of average video.
The increase in capacity from CD-ROM is due to: 1) smaller pit length (~2.08x), 2) tighter tracks (~2.16x), 3) slightly larger data area (~1.02x), 4) more efficient channel bit modulation (~1.06x), 5) more efficient error correction (~1.32x), 6) less sector overhead (~1.06x). Total increase for a single layer is about 7 times a standard CD-ROM. There's a slightly different explanation at <www.mpeg.org/MPEG/DVD/General/Gain.html>.
The capacity of a dual-layer disc is slightly less than double that of a single-layer disc. The laser has to read "through" the outer layer to the inner layer (a distance of 20 to 70 microns). To reduce inter-layer crosstalk, the minimum pit length of both layers is increased from 0.4 um to 0.44 um. To compensate, the reference scanning velocity is slightly faster, 3.84 m/s, as opposed to 3.49 m/s for single layer discs. Longer pits, spaced farther apart, are easier to read correctly and are less susceptible to jitter. The increased length means fewer pits per revolution, which results in reduced capacity per layer.
Note: Older versions of Windows that use FAT16 instead of UDF, FAT32, or NTFS to read a DVD may run into problems with the 4 gigabyte volume size limit. FAT16 also has a 2 gigabyte file size limit, while FAT32 has a 4 gigabyte file size limit. (NTFS has a 2 terabyte limit, so we're ok there for a while.)
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