Broadcasting over satellite, telecom, cable and terrestrial now turns into digital delivery using the MPEG-2/DVB standards. Digital broadcasting provides possibilities to build new streams by multiplexing broadcasting signals from different satellites, telecom networks and terrestrial transmissions. All or some of the signals may be scrambled, and conditional access will be widely used to control the access to the signals. The challenge for the network operator is to be able to transmultiplex signals from several different sources to make up a new transport stream in a cost-effective and DVB compliant way. In addition, it is necessary for the network operator to control the access to the different services in his own network. Transcontrol is passing control of conditional access from one operator to another operator at media boundaries by changing entitlement control messages (ECM) and entitlement management messages (EMM). Passing control of conditional access can also be done by transscrambling. The functional outline for transmultiplexing, transcontrol and transscrambling are given. Tandberg Television has gained experience in this field by the development and production of a transcontroller for the D2-MAC system and is using the TT7000 SmartMux platform to implement the "trans"-functions for MPEG-2/DVB signals at media boundaries.
展开▼
