H.264编码器降低运算复杂度的方法研究

【作者】 张进；

【导师】 姜威；

【作者基本信息】 山东大学 ， 通信与信息系统， 2006， 硕士

【摘要】 随着数字电视和视频的广泛应用，人们对图像的质量和应用提出了更高要求，希望能利用有限的空间和带宽资源存储和传输更多的视频数据，图像压缩技术已成为数据压缩的核心技术。最近，已成为热点的ITU-T H．264／AVC标准是由运动图像专家组(MPEG)与视频编码专家组(VCEG)共同制定的新一代图像压缩标准，它具有一系列优于H．263和MPEG4的新特性，可适应更高图像质量和低码速率应用的需求，该标准同时也作为ISO 14496—10／MPEG4 AVC标准。 H．264是新一代运动图像压缩标准，能提供比H．263／MPEG4更高的压缩性能，使图像的数据量减少50％，有利于用有限的空间存储更多的图像数据。对网络传输具有更好的支持，引入面向数据包编码，有利于将数据打包在网络中传输，支持流媒体服务应用。具有较强的抗误码特性，以适应在噪声干扰大、丢包率高的无线信道中传输。对不同应用的时延要求具有灵活的适应性。编码和解码复杂度具有可扩展性，支持编码和解码复杂度的不等分配和扩展。H．264／AVC优异的压缩性能将使其在数字电视广播、视频实时通信、网络视频流媒体传输以及多媒体短信等各个方面发挥重要的作用。但是H．264／AVC的压缩效率的提高是以增加运算的复杂度为代价的，如何降低编码器的运算复杂度，使其能适应视频实时通信的要求也就成了一个重要的问题。 本论文分四章。第一章主要讨论了当前视频编码的最新标准H．264技术，对整个标准的制定背景，应用范围和它的自身特点作了简要的介绍，并对其中一些关键技术作了比较详细地论述。第二章介绍运动估计的基本方法及H．264／AVC的运动估计。第三章对目前在降低编码器运算复杂度的各方面的算法进行了研究，分6个方面进行了介绍。降低编码器运算的复杂度需要将所有可能降低运算量的环节结合在一起，才能取得运算量的大幅度降低。第四章提出了一种运动矢量聚合模式选择算法，通过运动矢量的聚合过程得到宏块的模式划分，从而避免了采用率失真优化方法带来的庞大的计算量。理论分析及实验都证实了本算法有效的降低了编码器运算的复杂度，可以使用于可视电话，视频会议等实时视频通信中，尤其适合于资源有限的嵌入式硬件平台的H．264／AVC实时视频通信中。更多还原

【Abstract】 With the widespread adoption of technologies such as digital television, Internet streaming video and DVD-Video, video compression has become an essential component of broadcast and entertainment media, The Moving Picture Experts Group and the Video Coding Experts Group (MPEG and VCEG) have developed a new standard that promises to outperform than the earlier MPEG-4 and H.263 standards, providing better compression of video images. The new standard is entitled "Advanced Video Coding’ (AVC) and is published jointly as Part 10 of MPEG-4 and ITU-T Recommendation H.264/AVC .H.264/AVC provides mechanisms for coding video that are optimized for compression efficiency and aim to meet the needs of practical multimedia communication applications. The success of a practical implementation of H.264/AVC depends on careful design of the CODEC and effective choices of coding parameters. With the excellent compress performance of H.264/AVC,it will greatly be used in digital video broadcast ,internet video stream and multimedia communication. However the higher compress efficiency need even more complexity of computer, especially in the motion estimate .so it is very important to reduce the encoder’s computational complexity ,and enable it to used in real time communication .There is four chapter in this paper. The first chapter briefly introduced background of this standard, the application areas, and its design highlight feature . The second chapter introduced the basic method of motion estimate and the motion estimate of H.264. The third chapter is the core of this paper , It summarized the research on how to reduce the H.264/AVC encoder’s computational complexity at the present time ,and introduced in six side .In the fourth chapter I introduced a module select method of the macroblock based on the motion vector. It will avoid the Rdcost(rate distortion cost)and will obvious induce the computational complexity ,The theory analysis and the result of experimentations all show this arithmetic greatly induced the computational complexity of H.264/AVC. It can be used in the real time video communication such as video phone and video conference . It is especially suitable in video communication with embedded hardware which have limited resource.更多还原