针对H.264 Main profile中采用的CABAC解码算法,分别从逆二进制化数据查表、常规解码器归一化过程查找表和子区间定位查找表三个方面进行改进,避免了之前表格查找及分支判断耗费大量的时间,并在一定程度上减少了存储空间的使用,降低了...针对H.264 Main profile中采用的CABAC解码算法,分别从逆二进制化数据查表、常规解码器归一化过程查找表和子区间定位查找表三个方面进行改进,避免了之前表格查找及分支判断耗费大量的时间,并在一定程度上减少了存储空间的使用,降低了解码时间。经过测试,改进后的算法在速度上提高了45%左右,有一定的实用价值。展开更多
为解决最新一代视频压缩标准HEVC(High Efficiency Video Coding)中熵解码部分存在的语法元素串行依赖性问题,本文提出一种低时钟数冗余的CABAC(Context-BasedAdaptive Arithmetic Coding)硬件解码器实现方案.核心采用动态码表预处理方...为解决最新一代视频压缩标准HEVC(High Efficiency Video Coding)中熵解码部分存在的语法元素串行依赖性问题,本文提出一种低时钟数冗余的CABAC(Context-BasedAdaptive Arithmetic Coding)硬件解码器实现方案.核心采用动态码表预处理方式和并行处理电路设计,提高了时钟利用效率,满足HEVC Level4.1 Main Tier的全部要求,可以以40 MHz的时钟完成1080HD@60fps的视频实时解码.展开更多
Context-based adaptive binary arithmetic coding(CABAC) is the major entropy-coding algorithm employed in H.264/AVC.In this paper,we present a new VLSI architecture design for an H.264/AVC CABAC decoder,which optimizes...Context-based adaptive binary arithmetic coding(CABAC) is the major entropy-coding algorithm employed in H.264/AVC.In this paper,we present a new VLSI architecture design for an H.264/AVC CABAC decoder,which optimizes both decode decision and decode bypass engines for high throughput,and improves context model allocation for efficient external memory access.Based on the fact that the most possible symbol(MPS) branch is much simpler than the least possible symbol(LPS) branch,a newly organized decode decision engine consisting of two serially concatenated MPS branches and one LPS branch is proposed to achieve better parallelism at lower timing path cost.A look-ahead context index(ctxIdx) calculation mechanism is designed to provide the context model for the second MPS branch.A head-zero detector is proposed to improve the performance of the decode bypass engine according to UEGk encoding features.In addition,to lower the frequency of memory access,we reorganize the context models in external memory and use three circular buffers to cache the context models,neighboring information,and bit stream,respectively.A pre-fetching mechanism with a prediction scheme is adopted to load the corresponding content to a circular buffer to hide external memory latency.Experimental results show that our design can operate at 250 MHz with a 20.71k gate count in SMIC18 silicon technology,and that it achieves an average data decoding rate of 1.5 bins/cycle.展开更多
限制基于上下文的二进制算术解码(CABAD)速度的几个主要环节入手,提出了优化的上下文存储模式,改进的重归一化单元,并使用流水线提高解码速度.在Synopsys公司的CoCentric System Studio平台进行了二进制算术解码器体系结构设计,仿真结...限制基于上下文的二进制算术解码(CABAD)速度的几个主要环节入手,提出了优化的上下文存储模式,改进的重归一化单元,并使用流水线提高解码速度.在Synopsys公司的CoCentric System Studio平台进行了二进制算术解码器体系结构设计,仿真结果表明,本结构能够满足主要档次(main profile)CIF 30fps的实时解码的要求.展开更多
文摘针对H.264 Main profile中采用的CABAC解码算法,分别从逆二进制化数据查表、常规解码器归一化过程查找表和子区间定位查找表三个方面进行改进,避免了之前表格查找及分支判断耗费大量的时间,并在一定程度上减少了存储空间的使用,降低了解码时间。经过测试,改进后的算法在速度上提高了45%左右,有一定的实用价值。
文摘为解决最新一代视频压缩标准HEVC(High Efficiency Video Coding)中熵解码部分存在的语法元素串行依赖性问题,本文提出一种低时钟数冗余的CABAC(Context-BasedAdaptive Arithmetic Coding)硬件解码器实现方案.核心采用动态码表预处理方式和并行处理电路设计,提高了时钟利用效率,满足HEVC Level4.1 Main Tier的全部要求,可以以40 MHz的时钟完成1080HD@60fps的视频实时解码.
基金Project supported by the National Natural Science Foundation of China(No.61100074)the Fundamental Research Funds for the Central Universities,China(No.2013QNA5008)
文摘Context-based adaptive binary arithmetic coding(CABAC) is the major entropy-coding algorithm employed in H.264/AVC.In this paper,we present a new VLSI architecture design for an H.264/AVC CABAC decoder,which optimizes both decode decision and decode bypass engines for high throughput,and improves context model allocation for efficient external memory access.Based on the fact that the most possible symbol(MPS) branch is much simpler than the least possible symbol(LPS) branch,a newly organized decode decision engine consisting of two serially concatenated MPS branches and one LPS branch is proposed to achieve better parallelism at lower timing path cost.A look-ahead context index(ctxIdx) calculation mechanism is designed to provide the context model for the second MPS branch.A head-zero detector is proposed to improve the performance of the decode bypass engine according to UEGk encoding features.In addition,to lower the frequency of memory access,we reorganize the context models in external memory and use three circular buffers to cache the context models,neighboring information,and bit stream,respectively.A pre-fetching mechanism with a prediction scheme is adopted to load the corresponding content to a circular buffer to hide external memory latency.Experimental results show that our design can operate at 250 MHz with a 20.71k gate count in SMIC18 silicon technology,and that it achieves an average data decoding rate of 1.5 bins/cycle.
文摘限制基于上下文的二进制算术解码(CABAD)速度的几个主要环节入手,提出了优化的上下文存储模式,改进的重归一化单元,并使用流水线提高解码速度.在Synopsys公司的CoCentric System Studio平台进行了二进制算术解码器体系结构设计,仿真结果表明,本结构能够满足主要档次(main profile)CIF 30fps的实时解码的要求.
