Scrambling apparatus for digital multimedia broadcasting transmission system, produces entitlement control message packet using entitlement control message data of multimedia stream

摘要

The scrambling apparatus (120) has a demultiplexer for demulitplexing received multimedia stream and removing the null packet in the received multimedia stream. A scrambler scrambles the demultiplexed stream output by demultiplexer. An entitlement control message (ECM) packet generator produces ECM packet using ECM data of multimedia stream. A null packet generator produces a null packet based on the number of ECM packets. A multiplexer produces an output multimedia stream from the scrambled stream, ECM packet and the null packet produced by null packet generator. An independent claim is included for descrambling apparatus.