By Ron Gutman, Imagine Communications, Inc.
Cable operators need to rapidly expand bandwidth capacity to accommodate the emerging personalized and time-shifted viewing paradigm and the accelerating availability and demand for HD content. Linear programming, traditionally broadcast to subscribers using efficient high-end closedloop Variable Bit Rate (VBR) technology, will increasingly be delivered over on-demand networks which, using current Constant Bit Rate (CBR) technology, consume approximately 50% more bandwidth without matching the video quality of high-end broadcast VBR delivery. Although there have been a number of proponents of on-demand VBR, architectures and solutions based on broadcast-oriented rate-shaping technology inherently rely on performing both video processing and statistical multiplexing on each on-demand stream. Such approaches result in lower video quality than high-end broadcast VBR and a cost structure that is not viable for wide scale deployment in on-demand applications. In this paper we propose a new architecture that enables on-demand VBR by separating the video processing of each video asset from the downstream multiplexing of each stream to achieve the same video quality as broadcast VBR and eliminate the unnecessary and significant cost of reprocessing the same asset multiple times. This “never cover the same ground twice” approach makes VBR viable for on-demand services, and delivers the following value to system operators: • Clear and sustainable competitive advantage in video quality • Up to 50% gain in HFC bandwidth • Reduced overall CAPEX and OPEX • Uniform and controlled video quality across the entire network • Improved system availability • Increased service velocity