共查询到18条相似文献,搜索用时 703 毫秒
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H.264/AVC标准中的CABAC应用研究 总被引:3,自引:0,他引:3
H.264/AVC是由国际电信联盟(ITU)和国际标准化组织(ISO)共同制定的新一代视频编码标准。他的熵编码方案采纳了基于上下文的自适应二进制算术编码(CABAC)。CABAC是一种高效的熵编码,他利用上下文建模来降低符号间的冗余度,并且能够自适应码流的统计信息,获得很高的编码效率。深入研究了CABAC中的二进制化、上下文建模和自适应二进制算术编码器,并进行了相应的试验。实验结果表明:在相同的图像质量下,CABAC和CAVLC相比节省6%~15%的码率。 相似文献
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针对能够在FPGA 上实现实时解码H.264/AVC 高清晰视频序列码流的目标,本文提出了一种基于上下文的自适应二进制算术编码(CABAC)解码器的硬件设计结构,旨在解决解码过程中并行程度低,以及存储资源消耗大的问题.该设计对解码流程中的存储结构和关键路径进行优化,并采用了硬件加速,从而显著地提高了CABAC 的解码效率并充分利用了存储空间.测试结果表明,该方案能够满足H.264/AVC 高级档次高清视频序列实时解码系统的要求. 相似文献
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基于上下文的二进制算术编码(CABAC)是H.264/AVC中采用的一种高效的熵编码方法。本文简述算术编码的基本原理和CABAC的步骤.详细分析了二进制算术编码的过程。 相似文献
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H.264/AVC中二进制算术编码的分析与研究 总被引:1,自引:0,他引:1
算术编码是一种高效的熵编码方法,已经广泛应用于图像和视频编码中。文中简述了算术编码的基本原理,介绍了可行的算术编码算法,详细分析了H.264/AVC的CABAC中采用的自适应二进制算术编码的算法并对其性能进行了测试。 相似文献
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AVS+是我国2012年颁布的新一代视频编码标准。AVS+中采用了两种熵编码方法,一种是基于上下文的自适应变长编码CAVLC;另一种为基于上下文的自适应二进制算术编码CABAC。已经有人对H.264标准比较了两种编码体制的优劣,本文针对AVS+编码应用,简述分析二者算法原理,对照比较其特点,通过测试表明CABAC耗时稍长,但是比CAVLC更加高效。 相似文献
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H.264/AVC中基于上下文的自适应二进制算术编码 总被引:1,自引:0,他引:1
基于上下文自适应二进制算术编码(CABAC)H.264/AVC采用的高效熵编码方法之一,它由二进制化、上下文建模、算术编码三个步骤构成。详细阐述了CABAC的整个编码过程,并对它与VLC/CAVLC在编码性能上作了比较。 相似文献
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Since context-based adaptive binary arithmetic coding (CABAC) as the entropy coding method in H.264/AVC was originally designed
for lossy video compression, it is inappropriate for lossless video compression. Based on the fact that there are statistical
differences of residual data between lossy and lossless video compression, we propose an efficient differential pixel value
coding method in CABAC for H.264/AVC lossless video compression. Considering the observed statistical properties of the differential
pixel value in lossless coding, we modified the CABAC encoding mechanism with the newly designed binarization table and the
context-modeling method. Experimental results show that the proposed method achieves an approximately 12% bit saving, compared
to the original CABAC method in the H.264/AVC standard. 相似文献
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High efficiency video coding (HEVC) video codec applies different techniques in order to achieve high compression ratios and video quality that supports real-time applications. One of the critical techniques in HEVC is the Context adaptive Binary Arithmetic Coding (CABAC) which is type of entropy coding. CABAC comes at the cost of increased computational complexity, especially for parallelization and pipeline of these blocks: binarization, context modeling and binary arithmetic encoding. The Binarization (BZ) and de-Binarization (DBZ) methods are considered as important techniques in HEVC CABAC encoder and decoder respectively. Indeed, an important goal is to get high throughput in hardware architectures of CABAC BZ and DBZ in order to achieve high resolution applications. This work is the only one found on recent literature which focuses on design and implementation of full BZ and full DBZ compatible with H.265 and H.264. Consequently, a hardware architectures of BZ and DBZ are designed and implemented by using VHDL language, targeted an FPGA virtex4 xc4vsx25-12ff668 board and emulated with ModelSim. As a result, the implementation of BZ and DBZ can process 2 bins/cycle for each syntax element when operated at 697.83 MHz and 789.26 MHz, respectively. The proposed designs exhibits an improved high-throughput of 1395.66 Mbins/s for BZ and 1578.52 Mbins/s for the DBZ. The obtained Area Efficiencies in our proposed BZ and DBZ are about 0.544 Mbins/s/slices and 0.606 Mbins/s/slices, respectively, and it is better than many recent works. 相似文献
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H.264标准中的二进制算术编码算法复杂,用软件实现起来速度慢,编码一个信号需要多个时钟周期。结合硬件实现特点,对算法流程进行合理优化,采用流水线设计方法,电路结构采用Verilog HDL进行RTL级描述,在Synplify平台上进行FPGA综合,介绍了H.264中二进制算术编码的FPGA实现方案。编码速度达到1 b/cycle,工作频率达到75.7 MHz,完全可以应用于视频图像的实时编码中。 相似文献
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Marion Jeanne Christine Guillemot Thomas Guionnet Florelle Pauchet 《Signal, Image and Video Processing》2007,1(1):77-87
This paper addresses the problem of error-resilient decoding of bitstreams produced by the CABAC (context-based adaptive binary
arithmetic coding) algorithm used in the H.264 video coding standard. The paper describes a maximum a posteriori (MAP) estimation
algorithm improving the CABAC decoding performances in the presence of transmission errors. Methods improving the re-synchronization
and error detection capabilities of the decoder are then described. A variant of the CABAC algorithm supporting error detection
based on a forbidden interval is presented. The performances of the decoding algorithm are first assessed with theoretical
sources and by considering different binarization codes. They are compared against those obtained with Exp-Golomb codes and
with a transmission chain making use of an error-correcting code. The approach has been integrated in an H.264/MPEG-4 AVC
video coder and decoder. The PSNR gains obtained are discussed. 相似文献
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Context-based adaptive variable length coding (CAVLC) and context-based adaptive binary arithmetic coding (CABAC) are entropy coding methods employed in the H.264/AVC standard. Since these entropy coders are originally designed for encoding residual data, which are zigzag scanned and quantized transform coefficients, they cannot provide adequate coding performance for lossless video coding where residual data are not quantized transform coefficients, but the differential pixel values between the original and predicted pixel values. Therefore, considering the statistical characteristics of residual data in lossless video coding, we newly design each entropy coding method based on the conventional entropy coders in H.264/AVC. From the experimental result, we have verified that the proposed method provides not only positive bit-saving of 8% but also reduced computational complexity compared to the current H.264/AVC lossless coding mode. 相似文献
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H.264/AVC是由国际电信联盟和国际标准化组织共同制定的新一代视频编码标准。在该标准中,规定了两种熵编码的模式,即基于上下文的自适应二进制算术编码(Context-bsaed Adaptive Binary Arithmetic Coding,CABAC)和基于上下文自适应可变长编码(Context-bsaed Adaptive Variable-Length Coding,CAVLC)。其中,CABAC作为一种新型的熵编码方法,将自适应技术、上下文模型化和二进制算术编码有地的结合在一起,达到了较高的压缩效率,CABAC的框架中还使用了一些新颖的方法,使得CABAC在软硬件的实现上更加方便。为了验证CABAC的实际效果,笔者应用参考程序对其进行了直观的测试,实验结果表明:在相同图像质量下,CABAC和CAVLC相比的确能节省较大的平均比特率。 相似文献