Recordable discs
|
Type |
“Official” disc size (see Note) |
Computer disc size |
Disc size in megabits (less 4% for headroom) |
Notes on use |
|---|---|---|---|---|
|
DVD R |
8.4 GB |
7.9 GB |
64,512 Mbits |
These “write-once” discs work with many set-top players and DVD-ROM drives. Double-sided 4.7-GB discs are available, providing 9.4 GB of “official” disc space. A DVD-Video project fits on one side of a disc, so to use both sides you must create two separate projects. There are two competing “R” formats: DVD-R and DVD+R. Both formats provide the same level of compatibility with set-top players and DVD-ROM drives, but many DVD recorders support only one format. There are also two forms of DVD-R: “General” discs and “Authoring” discs. General discs can be used only in consumer DVD recorders. Authoring discs can be used only in professional recorders and cost much more than General discs. When buying discs, make sure to get the kind that your recorder supports. 3.95-GB “Authoring” discs seem to be more compatible with older DVD players, but are becoming rare. 8.4-GB dual-layer discs are just becoming available. Make sure your recorder supports these discs before buying them. 1.4-GB discs are designed for use in DVD camcorders but also work in other DVD recorders. |
|
4.7 GB per side |
4.38 GB per side |
36,096 Mbits per side | ||
|
3.95 GB |
3.68 GB |
30,336 Mbits | ||
|
1.4 GB |
1.3 GB |
10,752 Mbits | ||
|
DVD RW |
4.7 GB |
4.38 GB |
36,096 Mbits |
The rewritable version of DVD R. There are two competing “RW” formats: DVD-RW and DVD+RW. When buying discs, make sure you get the type that your recorder supports. These discs are compatible with fewer DVD-ROM drives and set-top players than DVD-R or DVD+R discs. Their main advantage is that they can be overwritten about 1,000 times, so you can use them for testing, or update the project later without having to use a new disc. |
|
1.4 GB |
1.3 GB |
10,752 Mbits | ||
|
DVD-RAM |
4.7 GB per side |
4.38 GB per side |
36,096 Mbits per side |
These discs were originally designed for data storage rather than DVD-Video. They can be played only in PC DVD-RAM drives and in a few DVD-ROM drives and set-top players. Discs can be single- or double-sided. A DVD project fits on one side; to use both sides you must create two separate projects. DVD-RAM discs can be overwritten about 100,000 times. |
|
2.6 GB per side |
2.42 GB per side |
19,968 Mbits per side | ||
|
1.4 GB per side |
1.3 GB per side |
10,752 Mbits per side |
Note: The “official” DVD disc sizes are confusing because they do not follow the conventions used for other digital media. In the DVD world, 1 Gigabyte is 1,000,000,000 (109) bytes, whereas in the computer world, 1 Gigabyte is 1,073,741,824 (230) bytes. Therefore a 4.7-GB DVD contains less data than a 4.7-GB hard disk.