|capacity||4.7 GB (single layer),
8.5 GB (dual layer)
|lifespan||about 10 years|
|size||12 cm x 1.2 mm|
Specification of the media
The DVD-ROM specification is the basis of all DVDs available up to now and defines the physical and logical format, i.e. the dimensions and the file system of the disc, the modulation method ( EFMplus ) and the error correction ( Reed-Solomon code ). But also:
- The reflectivity of the material (between 45% and 85% for the first layer - as opposed to around 80% for the CD - and between 13% and 35% for the second layer).
- The average data rate at which a DVD must at least be read.
- The storage capacities of all variants.
- The size of the data area per sector is 2048 bytes.
- The overhead that error correction can claim for itself (about 13%).
Norms and standards
- ISO / IEC 16448, based on the ECMA-268 standard for 80 mm DVDs
- ISO / IEC 16449, based on the ECMA-267 standard for 120 mm DVDs.