A real time multi-bin CABAC encoder for ultra high resolution video

Abstract

The demand for better quality pictures, smaller sizes, lower energy consumption, lower cost of appliances has been a fuel for creation of better compression standards and great compression rate. The outstanding compression competence of H.264/AVC is extensively used for video conferencing, online streaming and for HD television. Context Adaptive Binary Arithmetic Coding (CABAC) encoder is a vital part in H.264/AVC (Advanced Video Coding) main and high profiles that provides a real time encoding video of ultra high resolution. A CABAC compresses the components in the video signal according to the probability of those elements in a given context. CABAC encoder provides great compression rate over Context-Adaptive Variable Length Coding (CAVLC) baseline entropy encoder. An entropy encoder is a scheme used for lossless compression. A video sequence is a combination of bits which is referred as syntax element. The allocation of bits in various Syntax Elements (SE) [3] is analysed for the reduction in large amount of bit level operations involved and computational complexity involved. An optimised scheme for accessing the contexts and a Binary Arithmetic Encoder (BAE) capable of processing four bins per cycle m nm, is presented. Hence parallelism and throughput is achieved by the means of reduction in syntax and bit level dependency. The proposed fully hardwired encoder is synthesised towards a 90nm CMOS cell library in ASIC flow using Cadence RTL Compiler.