Single Chip Dual---Issue RISC Processor for Real---Time MPEG---2 Software Decoding

Abstract

A single chip system for real–time MPEG–2 decoding can be created by integrating a general purpose dual–issue RISC processor, with a small dedicated hardware for the variable length decoding (VLD) and block loading processes; a 32KB instruction RAM; and a 32KB data RAM. The VLD hardware performs Huffman decoding on the input data. The block loader performs the half–sample prediction for motion compensation and acts as a direct memory access (DMA) controller for the RISC processor by transferring data between an external 2MB DRAM and the internall 32 KB data RAM. The dual-issue RISC processor, running at 250MHz, is enhanced with a set of key sub-word and multimedia instructions for a sustained peak performance of 1000 MOPS. With this setup for MPEG-2 decoding applications, bi-directionally predicted non-intra video blocks are decoded in less than 800 cycles, leading to a single-chip, real-time MPEG-2 decoding system.