基于H．264的全高清解码器解决方案的研究

首先简要地叙述了H．264与其他标准相比所具有的优越性,接着系统地阐述了实现H．264全高清解码器的解决方案,并用JM平台对全高清的视频序列进行了解码测试,验证了软解码器方案不具备实时性,采用硬件解码器才是解决全高清视频解码的途径。     

Fast motion estimation for H.264

Several specific features have been incorporated into Motion estimation (ME) in H.264 coding standard to improve its coding efficiency. However, they result in very high computational load. In this paper, a fast ME algorithm is proposed to reduce the computational complexity. First, a mode discriminant method is used to free the encoder from checking the small block size modes in homogeneous regions. Second, a condensed hierarchical block matching method and a spatial neighbor searching scheme are employed to find the best full-pixel motion vector. Finally, direction-based selection rule is utilized to reduce the searching range in sub-pixel ME process. Experimental results on commonly used QCIF and CIF format test sequences have shown that the proposed algorithm achieves a reduction of 88% ME process time on average, while incurring only 0.033 dB loss in PSNR and 0.50% increment on the total bit rate compared with that of exhaustive ME process, which is a default approach adopted in the JM reference software.     

Efficient disparity vector prediction schemes with modified P frame for 2D camera arrays

An efficient disparity estimation algorithm for multi-view video sequences, recorded by a two-dimensional camera array in which the cameras are spaced equidistantly, is presented. Because of the strong geometrical relationship among views, the disparity vectors of a certain view can for most blocks be derived from the disparity vectors of other views. A frame constructed using that idea is called a D frame in this work. Three new prediction schemes which contain D frames are proposed for encoding 5 × 3 multi-view video sequences. The schemes are applied to several multi-view image sequences taken from a camera-array and they are compared in terms of quality, bit-rate and complexity. The experimental results show that the proposed prediction schemes significantly decrease the complexity of the encoder at a very low cost of quality and/or bit-rate.     

基于兰氏距离的H.264/AVC帧内快速算法

提出了一种帧内模式快速选择算法。利用宏块内部相邻像素值的差异判定宏块的类型,再进行Intra_4×4和Intra_16×16两种模式的快速选择。对于Intra_4×4模式,利用兰氏距离提取4×4块的纹理方向,根据纹理方向进行Intra_4×4模式的快速选择。实验结果表明,所提算法在峰值信噪比(PSNR)和码率变化不大的情况下,显著地提高了编码速度。     

基于TinySwitch—II的双路隔离输出开关电源设计

在某些特定电路场合,需要提供多路的隔离直流电源。对于多路隔离输出的开关电源,不能采用多路共地输出开关电源的常用方法来提高其交叉调整率,而隔离式的方法却设计复杂。文中设计了一种基于Tiny SwitchII芯片TNY264的小功率双路隔离输出的开关电源,采用线性稳压芯片对辅助回路进行稳压的方法,设计简单易行,并给出了高频变压器的详细设计过程。设计结果测试表明,设计的开关电源具有很好的电压调整率和负载调整率。     

基于分裂聚合块模式选择的运动估计算法

为了简化H.264视频压缩编码标准中庞大的计算量,提出了一种基于分裂聚合块模式选择的运动估计算法.该算法结合H.264标准7种可变块尺寸模式,利用分裂聚合原理,为帧间运动估计提前确定块模式.保证在图像质量允许的前提下,提高编码效率,为各种多媒体需求的广泛应用奠定基础.     

H.264中帧内编码算法及其快速实现研究

新的视频编码标准H.264使用了帧内预测的编码方式,这与以往的视频编码标准相比在很大程度上提高了帧内编码效率,节省了码流,但同时也增加了编码器的复杂度,因此有必要对H.264帧内编码算法进行快速实现,以满足实时视频通信的要求.首先详细介绍H.264帧内编码的实现过程,然后使用SIMD(单指令多数据流)技术对帧内编码进行快速实现.实验结果表明,与未使用快速算法相比,使用该快速实现算法后,H.264帧内编码速度得到显著提高.     

基于3G无线网络的视频监控系统前端设计

介绍了一种以ARM926-EJS微处理器为主控制器、Linux为操作系统、WCDMA网络为传输网络的视频监控系统前端。给出了视频监控系统前端的硬件设计、软件设计。重点介绍了视频采集、压缩编码、无线发送过程。将视频监控系统前端输出的H.264视频流封装成大小合适的RTP数据包,然后通过IEEE 802.11g无线传输模块发送到3G传输网络。经实验证明,该系统具有较好的实时性和可靠性,在抢险救灾等领域得到了较广泛的应用。     

漫谈高清节目技术标准与发展意义

从理论与实践两方面入手,在理论方面重点阐述高清节目编码标准和存储技术,在实践方面主要介绍高清节目在数字电视网络中和日常生活中的应用。使读者能够进一步理清高清视频格式之间的内在联系与区别,同时也可加深理解高清节目对于数字电视未来发展的意义。     

Motion-compensated DCT temporal filters for efficient spatio-temporal scalable video coding

Although most of the proposals for implementing motion-compensated temporal filtering (MCTF) schemes are based on the wavelet transform, in this paper, we propose an MCTF framework based on the discrete cosine transform (DCT). Using DCT decimation and interpolation, several temporal decomposition structures named motion-compensated DCT temporal filters (MCDCT-TF) are introduced. These structures are able to employ filters of any length with particular emphasis on 5/3 DCT and 7/4 DCT. The proposed MCDCT-TF and the two-dimensional (2D) DCT decimation technique are incorporated into H.264/AVC to provide spatio-temporal scalability. Compared with the current MCTF-based lifting schemes such as Haar, and 5/3 wavelet filters, simulation results show that the proposed MCDCT-TF utilizing longer tap DCT filters achieves a significant improvement in coding gain. The impact of odd/even group of frames, the decimation/interpolation ratios, and motion-compensated connectivity on the MCDCT-TF performance are also analyzed. Moreover, simulation results show that the performance of the presented scalable video coding is close to the single layer H.264/AVC and is slightly inferior to the temporal scalability supported in JSVM, the state-of-the-art scalable video coding standard, that gets its gain from Hierarchical B-pictures. However, our spatio-temporal coding scheme outperforms the spatio-temporal supported in JSVM even if it uses hierarchical B-pictures to improve its gain.