Error Concealment Using Inter‐layer Correlation for Scalable Video Coding

In this paper, we propose a new error concealment (EC) method using inter‐layer correlation for scalable video coding. In the proposed method, the auxiliary motion vector (MV) and the auxiliary mode number (MN) of intra prediction are interleaved into the bitstream to recover the corrupted frame. In order to reduce the bit rate, the proposed method encodes the difference between the original and the predicted values of the MV and MN instead of the original values. Experimental results show that the proposed EC outperforms the conventional EC by 2.8 dB to 6.7 dB.     

Comparing the streaming of FGS encoded video at different aggregation levels: frame,GoP, and scene

Fine granularity scalability (FGS), a new coding technique that has recently been added to the MPEG‐4 video coding standard, allows for the flexible scaling of each individual video frame at very fine granularity. This flexibility makes FGS video very well suited for rate‐distortion optimized streaming mechanisms, which minimize the distortion (i.e. maximize the quality) of the streamed video by transmitting the optimal number of bits for each individual frame. The per‐frame optimization of the transmission schedule, however, puts a significant computational burden on video servers and intermediate streaming gateways. In this paper we investigate the rate‐distortion optimized streaming at different video frame aggregation levels. We find that compared to the optimization for each individual video frame, optimization at the level of video scenes reduces the computational effort dramatically, while reducing the video quality only very slightly. Copyright © 2005 John Wiley & Sons, Ltd.     

基于模型的H263＋可扩展性编码

提出了基于模型的视频时空可扩展性编码方法，即根据人眼视觉敏感程度的不同，将视频中的每帧图象根据模型划分为程度不同的区域，对每一个区域分配不同的时间和空间分辨率，以期在极低码率的传送环境中保证人眼敏感区域的图象质量和传送效率。     

可扩展的冲击—接触并行计算研究

冲击—接触计算模型在汽车碰撞、金属成型等的模拟计算中有着广泛的应用，鉴于冲击—接触计算过程复杂和计算量大，本文在分布式可扩展的并行计算平台上，设计并实现了冲击—接触的并行计算。算例证明，计算平台稳定可靠，算法简单实用，且具有较好的并行效率和可扩展性。     

Scalable modeling and comparison for spiral inductors using enhanced 1-π and 2-π topologies

Two different scalable models developed based on enhanced 1-πand 2-πtopologies are presented for onchip spiral inductor modeling.All elements used in the two topologies for accurately predicting the characteristics of spiral inductors at radio frequencies are constructed in geometry-dependent equations for scalable modeling.Then a comparison between the 1-πand 2-πscalable models is made from the following aspects:the complexity of equivalent circuit models and parameter-extraction procedures,scalable rul...     

基于SVC码流自适应机制的视频转码技术

针对现有转码技术中存在的转码质量低、运算复杂度高、存储容量大和成本高等缺陷,提出一种转码改进方法,将SVC(scalable video coding)应用到转码中以解决以上问题。将改进方法与传统转码技术进行了比较,实验证明,基于SVC的转码不仅复杂度大大降低,并且RD性能也优于传统转码。     

可伸缩性视频编码的码率分配算法

本文研究了渐进的精细的可伸缩性(Progressive Fine Granular Scalable,PFGS)视频编码的增强层码流的码率分配问题,它是由PFGS各帧的增强层码流长度不同引起的.我们首先建立了PFGS增强层的多帧联合的率失真(rate-distortion,R-D)函数,并通过MPEG-4标准测试序列检验了它的正确性.然后利用联合率失真函数给出了局部最优的码率分配算法,并进行了简化使得它的复杂性极低,非常适合流化视频(streaming video)服务器使用.实验结果显示本文提出的算法不仅使得各帧图像的解码质量比较平衡,而且将PFGS的编码效率提高了将近0.5dB.     

Network-Adaptive Rate Control and Unequal Loss Protection with TCP-Friendly Protocol for Scalable Video Over Internet

Video communication with Quality of Service (QoS) is an important and challenging task. To have QoS provision at application level in the current best-effort Internet, rate control, congestion control and error control are several effective approaches. In this paper, we propose a new network-adaptive rate control and Unequal Loss Protection (ULP) scheme in conjunction with TCP-friendly congestion control for scalable video streaming. Our proposed approach is capable of simultaneously controlling congestion and packet loss occurred across the Internet. More specifically, we first dynamically estimate the available network bandwidth on the fly. Then, TCP-friendly congestion control is performed to smoothly adjust the sending rate for transmission of continuous media. Considering the characteristic of scalable video, unequal loss protection at packet level is adopted for different video layers while performing congestion control. Consequently, a fixed-length and priority-based packetization scheme is introduced to enhance the capability of loss protection and improve the efficiency of network-bandwidth utilization. Moreover, Rate-Distortion (R-D) based bit allocation is proposed to minimize the expected end-to-end distortion. Simulation results demonstrate the effectiveness of our proposed scheme.     

服务质量控制粒度及基本细粒度编码算法研究

文章以视频服务质量控制的粒度为主线，分析了不同控制粒度的服务对网络状态变迁的响应特征．并探索了研究网络状态和QoS控制粒度之间的映射关系所必须解决的关键问题。在此基础上，进一步分析了位面编码、离散小波变换和MP变换编码三种基本细粒度视频编码算法的理论基础、实现方式和各自的特点。分析表明它们适用于不同的应用场合。     

复杂网络与可扩展路由

互联网规模扩大,相应路由表大小呈指数增加,形成下一代互联网可扩展路由“瓶颈”。基于复杂网络和可扩展路由的相关理论与主要策略,文章对相关研究成果。如小世界效应所表现出来的特性、小世界和无标度网络模型,网格、层次及隐藏度量等3种可扩展路由网络模型,随机游走、贪婪、最大度、优先、本地介数、距离与度及相似性与度混合等多种路由策略等进行了分析与归纳。这些研究结果和方法为因互联网规模不断扩大所带来的路由系统可扩展性问题提供解决方案