By AdamS. Tom, Ph.D., Imedia Corporation
''Be careful what you wish for" could be the watchword for the cable industry with digital television. After years of advocacy for the technical superiority of digital compression and modulation, digital broadcasting, from standard definition television (SDTV) to high definition television (HDTV), should reign supreme by the middle of the next decade. 1he greatest challenge for cable operators here will be to respond to the market-driven, multiple-sourced expansion of demands to deliver customized programming with ad insertion, video on demand (VOD) and even data-casting, Internet access, telephony and interactivity capabilities for the individual cable operator.
MPEG-2 multiplexes from remote and local sources must be processed through a demultiplexer, transcoded and then remultiplexed to form the outgoing multiplex. To transmit a coherent outgoing program transport stream with good picture quality, this process must include parsing, synchronized scheduling, stream transcoding and splicing, and analysis and service information editing.
To gain the increased revenue opportunities of customized programming, this process must also maximize bandwidth. media's statistical re-multiplexing optimizes compression ratios without feedback, separates the encoder from the multiplexer and • seamlessly switches and splices MPEG-2 programming in real time. This supports the capability to selectively groom programs to create a new statistical multiplex customized for a cable system and transmit it over the space of a single analog channel.