Why is (was) Constrained Parameters so important?
A. It is an optimum point that allows (just barely) cost effective VLSI implementations in 1992 technology (0.8 microns). It also implies a nominal guarantee of interoperability for decoders and a reasonable class of performance for encoders. Since CPB is the most popular canonical MPEG-1 conformance point, MPEG devices which are not capable of at least meeting SIF rates are usually not considered to be true MPEG by industry. Picture buffers (i.e. “frame stores”) and coded data buffering requirements for MPEG-1 CPB fit just snugly into 4 Mbit of memory (DRAM). Who uses constrained parameters bitstreams? A. Principal CPB applications are Compact Disc video (White Book or CD-I) and desktop video. Set-top TV decoders fall into a higher sampling rate category known as “CCIR 601” or “Broadcast rate,” which as a rule of thumb, has sampling dimensions and bandwidth 4 times that of SIF (Constrained Parameter sample rate limit). Are there ways of circumventing constrained parameters bitstreams
