摘要High Efficiency Video Coding (HEVC),也称作H.265，是最新一代的视频编码标准。标准由视频编码联合工作组 ( Joint Collaborative Team on Video Coding , JCT-VC )于2010年在德国德累斯顿的第一次大会上正式提出。大会中JCT-VC挑选了一些针对视频编码的高效的优化方案收入新标准HEVC。HEVC标准的视频压缩新能几乎是上一代标准H.264的两倍，而同时其编码的复杂度也伴随着压缩性能的提高而提高。61122

    虽然HEVC上处于发展之中，JCT-VC的会议也在不断召开，每次会议都会对HEVC进行改进。与H.264/AVC相比，HEVC中采用了新的编码结构，其中包括编码单元、预测单元以及变换单元。他们的具体功能在下面的章节有描述。另一显著的改变时HEVC中的块大小选择更多，且最高达到了64*64的大小。

    针对HEVC中的熵编码部分在下文中进行了研究。HEVC中原本包含了两种熵编码模式，由于其中CABAC方式更为常用以及高效，所以在此主要研究了CABAC的原理以及具体流程。它的主要步骤分别为二进制化、上下文建模以及算术编码。最后比较了HEVC相对于H.264/AVC两大标准中熵编码部分的区别以及改进。

毕业论文关键词：HEVC 熵编码 CABAC 二进制化

Abstract  High Efficiency Video Coding,also known as H.265,is a new video coding standard.This standard is developed by the Joint Collaborative Team on Video Coding , JCT-VC.It was proposed during the first meeting of JCT-VC in 2010 in Dresden,German.JCT-VC selected a few video coding schemes with higher efficiency.The new standard HEVC’s performance in video compressing is nearly two times as H.264/AVC’s,but the coding complexity also grows dramatically.

  HEVC is still working in progress.As the JCT-VC meetings keep convening,HEVC improves steadily.Comparing with the H.264/AVC standard,HEVC adopts a new coding structure,which is more flexible,including the Coding Unit,the Prediction Unit and the Transform Unit.Their functions are introduced in the  following Chapters.Another significant change is that there are more options for the size of blocks,the largest of them reaches 64*64.

  The entropy coding part is studied in this paper.There were two entropy tools in HEVC,while the CABAC is the one with higher efficiency and more common in use.And thus we mainly discussed the process and the principles of CABAC in HEVC.The process of CABAC is roughly pided into the following three steps:Binarization,context modeling and arithmetic coding.

  In the end,the differences and improvements between the entropy part of HEVC and H.264/AVC are discussed.

Key words:HEVC   Entropy coding    CABAC    Binarization 

1  绪论 4

2  HEVC标准介绍及熵编码原理简介 4

2.1  HEVC标准简介 4

2.1.1  HEVC的基本框架 4

2.1.2  HEVC的图像表达 5

2.1.2.1  编码单元 5

2.1.2.2  预测单元 6

2.1.2.3  变换单元 6

2.2  编码原理简介 7

2.2.1  Huffman编码 7

2.2.2  算术编码 8

2.2.3  自适应算术编码基本原理 10

2.2.4  基于上下文匹配的自适应算术编码原理 11

2.2.5  二进制算术编码原理