DVD disc Category3
1.DVD-5 specification: One-sided monolayer, therefore the standard material record quantity is 4.7GB. At present in market by this kind of specification DVD compact disc majority, because this specification's production maturity is highest. 2. DVD-l0 specification: Two-sided monolayers, is also the DVD piece pro and con surface may store up the material, therefore the standard material record quantity is 9.4GB, is DVD-5 two times. one-sided list/double-decked small dish piece 3. DVD-9 specification: One-sided double-decked, is also increases the material level to two, middle inserts a translucent reflection layer, then reads the second material time, does not need to turn hostile the DVD disk sheet, cut the laser read head's focusing position to be possible directly. In the theory, the material record quantity may promote to 9.4GB , but as a result of the double-decked structure can the unwanted signal stability, therefore the highest material record quantity in fact can only achieve 8.5GB. 4. DVD-l8 specification: DVD-9 two-sided, the capacity may reach as high as l7GB. (only aims at DVD-VIDEO) according to the DVD disk sheet's area code classification the US Film society to protect own benefit, requests each DVD manufacturer addition “against copy system”, simultaneously arranges the note different area code on the DVD disk sheet, like this, only then conforms to the area code condition limit area to be able to broadcast the corresponding DVD plate, simultaneously has also limited DVD to equipment's and so on videocorder duplications. Because each movie screens the time in the world to be different, to avoid before the movie screens DVD to sell in advance causes the box office the reduction, therefore uses the area code to control, when after some area's movie screens, only then promotes Canada to have this local code DVD video disk.