What is DVB?
DVB (Digital Video Broadcasting) is the standard for digital TV.
Widely used in Europe. USA's Dish Network and DirecTV use proprietary, deliberately incompatible variants of it.
It's based on MPEG2 compression and packet formats. The physical part comes in the variants
- terrestrial (antenna, airwaves) (DVB-T)
- cable (DVB-C)
- satellite (DVB-S)
Some channels (esp. pay channels) are encrypted, there's a standardized decryption hardware slot called "Common Interface" (CI) for the decryption hardware called "Conditional Access Module" (CAM), which usually also needs a smartcard for legitimation/accounting.
There are several hundred or thousand DVB-S channels available in Europe, e.g. over the satellite fleets Astra and Eutelsat, almost all of them "free to air" (unencrypted), including all the major free stations. DVB-T is (being) deployed at the moment in UK, Germany, Australia and other countries as a replacement for the classic analog TV over antenna.