A high speed 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. 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 bits simultaneously 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.