By Paul Harr, Scientific-Atlanta, Inc.
Cable Programmers are faced with a multitude of challenges as they move to digital. Maintaining the flexibility of their existing analog systems today must be weighed against the cost of the equipment that it will take to provide that same flexibility in a digital architecture. An architecture that allows the cable programmer the same flexibility as analog is one that incorporates high definition (HD) and standard definition (SD) digital encoders. In this architecture the program element streams are demultiplexed and switched to allow for commercial insertion. This option however, will be expensive as the cost of decoding and encoding is high today will likely remain so for the foreseeable future. On the other hand, lower cost options will exist that include processing the incoming programmer and broadcast signals at the transport stream level. This option, however, provides less flexibility than program stream switching. Program streams are not demultiplexed and therefore do not allow seamless insertion of commercial ads. Technologies are becoming available which provide switching between multiple signals at the transport layer. This paper will compare high cost / high flexibility technology with lower cost / lower flexibility technology for cable headends.