Error resilient video over multimedia broadcast multicast services (MBMS)

With available data rates for mobile devices constantly increasing, services such as video broadcast and multicast are becoming feasible. A new standard called Multimedia Broadcast Multicast Services (MBMS) is being developed by 3GPP to enable new class of spectrum-efficient multimedia services. Multicast services are expected to serve a diverse user base with varying connectivity and capabilities. We analyze the problem of video error resilience in MBMS services that is critical to maintain consistent quality for end users. The existing error resilience techniques for IP multicasting are not applicable in the MBMS environment. In this paper, we present error resilience techniques that are applicable within the context of the MBMS standard. We propose an Intra Block Refresh method for MBMS services and the results show improved performance. We develop a methodology that can be applied to adapting traditional error resilience tools for the MBMS environment.     

An enhanced framework for providing multimedia broadcast/multicast service over heterogeneous networks

Multimedia broadcast multicast service （MBMS） with inherently low requirement for network resources has been proposed as a candidate solution for using such resources in a more efficient manner. On the other hand, the Next Generation Mobile Network （NGMN） combines multiple radio access technologies （RATs） to optimize overall network performance. Handover performance is becoming a vital indicator of the quality experience of mobile user equipment （UE）. In contrast to the conventional vertical handover issue, the problem we are facing is how to seamlessly transmit broadcast/multicast sessions among heterogeneous networks. In this paper, we propose a new network entity, media independent broadcast multicast service center （MIBM-SC）, to provide seamless handover for broadcast/multicast sessions over heterogeneous networks, by extensions and enhancements of MBMS and media independent information service （MIIS） architectures. Additionally, a network selection scheme and a cell transmission mode selection scheme are proposed for selecting the best target network and best transmission mode. Both schemes are based on a load-aware network capacity estimation algorithm. Simulation results show that the pro- posed approach has the capability to provide MBMS over heterogeneous networks, with improved handover performance in terms of packet loss rate, throughput, handover delay, cell load, bandwidth usage, and the peak signal-to-noise ratio （PSNR）.     

Enhancing wireless video streaming using lightweight approximate authentication

In this paper, we propose a novel lightweight approximate authentication algorithm that provides efficient protection for wireless video streaming where attacks on the stream are possible, but classical integrity protection algorithms are impractical because bit errors occur naturally. The benefits of the proposed algorithm over other algorithms are fast execution and small message authentication code size. Moreover, the approximate authentication supports error resilient video decoding by dropping seriously damaged packets, thus improving the perceived quality of the video stream. The performance of the algorithm is demonstrated via numerical analysis, simulations and measurements over modeled and real wireless channels.     

Real-time software-based video coder for multimedia communication systems

A novel software-based video compression algorithm, the Popular Video Coder (PVC), is presented in this paper, and a video phone system, the Popular Phone, is also implemented based on the PVC. The PVC simplifies the traditional video coder by removing the transform and the motion estimation parts and modifies the quantizer and entropy coder. Two novel coding algorithms, the adaptive quantizer and the modified windowed Huffman-like coder, are used in the PVC to encode the video data with a quality picture at a high compression ratio. The video quality of the proposed coder is as good as that of the MPEG coder when the input is a low-resolution and slow-motion video, and the computational complexity of the PVC is much lower than that of the Motion Picture Expert Group (MPEG). Since no compression hardware is needed for the PVC to encode and decode video data, the cost and complexity of developing multimedia applications, such as video phone and multimedia e-mail systems, can be greatly reduced. Furthermore, some networking issues, such as error control and flow control, are discussed in connection with applying the PVC to implement the Popular Phone.     

An FEC scheme combined with weighted scheduling to reduce multicast packet loss in IPTV over PON

Congestion is one of the most important challenges in optical networks. In a Passive Optical Network (PON), the Optical Line Terminal (OLT) is a bottleneck and congestion prone. In this paper, a framework is proposed with Forward Error Correction (FEC) at the IP layer combined with Weighted Round Robin (WRR) at the scheduling level to overcome packet-loss due to congestion in the OLT in order to achieve efficient video multicasting over PON. In the FEC scheme, Reed-Solomon (RS(n,k)) with erasure coding is used, where (n−k) erroneous symbols per n symbol blocks can be corrected. In our framework, an Internet Protocol TeleVision (IPTV) service provider uses the mentioned RS coding and generates redundant packets from regular IPTV packets in such a way that an Optical Network Unit (ONU) can recover lost packets from received packets, thus resulting in a better video quality. Simulation results show that using the proposed framework, an ONU can recover many lost packets and achieve better video quality under different traffic loads for its users. For instance, the proposed method can reduce packet loss rate by almost 55% and 10% under traffic load 0.9, respectively, compared with the Round Robin (RR) and WRR methods under symmetric traffic load. When High Receivers Queue (HRQ) traffic (i.e., traffic received by many users) is twice Low Receivers Queue (LRQ) traffic (i.e., traffic received by a small number of users), this reduction is almost 86% and 30% under traffic load 0.9. Finally, when LRQ traffic is twice HRQ traffic, the reduction in packet loss rate is almost 70% and 91% at traffic load 0.5.     

Large-scale multimedia content delivery over optical networks for interactive TV services

iTVP is a system built for delivery of live TV programming, video-on-demand and audio-on-demand with interactive access over IP networks. It has a nationwide range and is designed to provide service to a high number of concurrent users. Hence, scalability is one of the most important issues. In this paper we described how scalability is achieved in a two-level hierarchical architecture of the delivery system. We present the principles of content caching mechanisms and the management of the resulting distributed content repository. The system is implemented and currently operates in a test installation. Although the range of the test system operations is limited, as far as the number of users and the size of the content repository is concerned, the experience gained with iTVP so far provides an insight into the expected prototype performance. We present a system performance evaluation and describe the experience gained during the iGrid demonstration.     

WMSN中的分布式视频编码GOP大小控制方法

针对分布式视频编码（DVC）序列在无线多媒体传感器网络（WMSN）中传输可靠性较低的问题,提出了一种考虑节点能耗的图像组（GOP）大小控制方法。该方法分析了DVC编码框架及节点的能量消耗情况,定义了节点的可用度和帧的活动度,并对分布式视频编码序列在编码和传输过程的能耗进行了计算。在此基础上,综合考虑帧的活动度与节点能耗,实现了对分布式视频编码GOP大小的有效控制。仿真实验结果表明,与现有的GOP大小控制方法相比,该方法提高了无线多媒体传感器网络中的DVC序列的峰值信噪比,降低了节点的平均能耗,其传输可靠性也得到了显著改善。     

KAIST image computing system (KICS): A parallel architecture for real-time multimedia data processing

An efficient parallel architecture is proposed for high-performance multimedia data processing using multiple multimedia video processors (MVP; TMS320C80), which are fully programmable general digital signal processors (DSP). This paper describes several requirements for a multimedia data processing system and the system architecture of an image computing system called the KAIST Image Computing System (KICS). The performance of the KICS is evaluated in terms of its I/O bandwidth and the execution time for some image processing functions. An application of the KICS to the real-time Moving Picture Expert Group 2 (MPEG-2) encoder is introduced. The programmability and the high-speed data-access capability of the KICS are its most important features as a high-performance system for real-time multimedia data processing.     

Full-sharing: efficient bandwidth scheduling for video streaming over broadband cable networks (BCNs)

Broadband Cable Networks (BCNs) bring high-speed Internet access to home and make emerging multimedia streaming applications feasible. However, bandwidth contention is still a challenging problem in providing efficient IP-based Video-On-Demand (VOD) service on BCNs, due to the lack of effective approaches to exploit the unique characteristics of BCNs. To address the bandwidth contention issue, we propose an efficient video scheduling technique, called full-sharing scheduling in this paper. This technique fully exploits the unique characteristics of BCNs to reduce the bandwidth consumption of video sessions sharing a cable channel of fixed capacity, thereby maximizing the number of simultaneous video sessions on the single channel. Furthermore, we analyze the expected bandwidth and the session blocking probability of a video under the full-sharing scheduling. Based on this analysis, we design an efficient video assignment mechanism for maximizing the profit of a VOD system in scheduling videos on BCNs. Through both analysis and simulation, we show that our approach minimizes the bandwidth consumption of video sessions compared with the previous approaches and has significant advantages on BCNs. The proposed approach is also directly applicable on other broadcast/multicast networks in which clients have sufficient buffer and downstream bandwidth, e.g., satellite broadband networks. This work was supported in part by the National Science Foundation under the grants ANI-0073819, ITR-0085824, and CAREER Award NCR-9734428. Any opinions, findings, and conclusions or recommendations expressed in this paper are those of the authors and do not necessarily reflect the views of the National Science Foundation.     

Traffic characterization algorithms for VBR video in multimedia networks

A network that offers deterministic, i.e., worst case, quality-of-service guarantees to variable-bit-rate (VBR) video must provide a resource reservation mechanism that allocates bandwidth, buffer space, and other resources for each video stream. Such a resource reservation scheme must be carefully designed, otherwise network resources are wasted. A key component for the design of a resource reservation scheme is the traffic characterization method that specifies the traffic arrivals on a video stream. The traffic characterization should accurately describe the actual arrivals, so that a large number of streams can be supported; but it must also map directly into efficient traffic-policing mechanisms that monitor arrivals on each stream. In this study, we present a fast and accurate traffic characterization method for stored VBR video in networks with a deterministic service. We use this approximation to obtain a traffic characterization that can be efficiently policed by a small number of leaky buckets. We present a case study where we apply our characterization method to networks that employ a dynamic resource reservation scheme with renegotiation. We use traces from a set of 25–30-min MPEG sequences to evaluate our method against other characterization schemes from the literature.     

Perceptions versus expectations of multimedia messaging service (MMS)

Previously mobile industry has been unsuccessful in predicting services available on mobile phones that consumers would want to use. Short messaging service (SMS), for example, developed as a major service to the surprise of service providers. Wireless application protocol (WAP) despite heavy marketing and high hopes was not successful. The study presented examines consumer attitudes to using multimedia messaging service (MMS). An experiment is reported which tests whether people who had the opportunity to use MMS formed different perceptions of it to those who were only shown an animated PowerPoint presentation. The results demonstrated that the group who used MMS had more positive perceptions. However, the results from both groups suggest there are important barriers to overcome for use to be extensive: for example, the price of the service and of the handsets would be a disincentive and the service would need to be available to use across networks.     

基于三维集合分裂嵌入式块编码(3D-SPECK)的视频编码器

提出了一种基于三维SPECK(Set Partitioned Embedded Block)编码方法的视频编码器。为了进行三维小波变换,视频序列被组织成帧组(GOP,Group of Frames),变换后的小波系数被组织成小波方格(WC,Wavelet Cube)。通过采用3D-SPECK对WC进行有效地编码,从而实现视频序列的有效编码。时域上放弃了运动估计和运动补偿,采用了时间轴上的小波变换,因此该编码器与传统的混合编码模式相比,具有计算量小的优点。实验结果表明,该编码器无论在数值结论还是主观效果上都与无运动补偿的3D-SPIHT(Set Partitioning in Hierarchical Trees)相当。     

A novel hybrid 3D video service algorithm based on scalable video coding (SVC) technology

A scalable video coding (SVC) server can simultaneously provide a single bitstream with a fixed maximum service layer for different kinds of devices having different memory capacity, network bandwidth, and CPU performance requirements. An efficient hybrid 3D video service scheme is proposed without violation of the SVC standard technology for multiple transmission paths. A dynamic local disparity vector estimation algorithm is used to reflect the motion shift component between stereo views in the inter-layer prediction stage of the SVC encoder. To improve the coding efficiency, an adaptive search scheme based on distortion rates (DRs) between corresponding and reference macroblocks is used. Based on experimental results, up to 1.41 dB of quality improvement using JSVM 9.19 reference software is verified.     

IP网中多媒体表现质量控制的算法研究

提出在目前IP网络设备及技术基础上,一种在通信子网外优化多媒体表现质量的源端最小延迟表现算法。给出并证明了分布式多媒体应用同步表现最优化定理,进而提出最小聚类延迟表现算法作为源端最小延迟表现控制算法的改进。与古典列表调度算法比较得出,上述两种算法能实现优化的分布式多媒体同步表现,同时在目的端缓冲区需求、溢出可能性等方面具有更优的性能。上述算法与底层通信机制无关,未来具有广阔的发展及应用前景。     

A Fifth Order Runge-Kutta RK(5, 5) Method With Error Control

In this paper a new Runge-Kutta RK(5, 5) method is introduced. The theory and analysis of its properties are investigated and compared with the more well known RKF(4, 5) and RK(4, 5) - Merson methods.     

Experiments with video transmission over an Asynchronous Transfer Mode (ATM) network

We present end-to-end performance of digital coded video (JPEG, MPEG-1, and MPEG-2) over a local asynchronuous transfer mode (ATM) network. We discuss performance in terms of both delay (jitter) and frame loss as a function of load. The experimental data reveal that the burstiness of the variable bit-rate-coded video streams degrades the performance significantly when the hosts and the network are stressed. Our results show that traffic smoothing decreases frame loss significantly while maintaining acceptable jitter and loss bounds. We also discuss requirements for system components, such as the network interface and switch, which are necessary to support video services efficiently.     

Error Concealment Using Adaptive Multilayer Perceptrons (MLPs) for Block-Based Image Coding

Image coding algorithms such as Vector Quantisation (VQ), JPEG and MPEG have been widely used for encoding image and video. These compression systems utilise block-based coding techniques to achieve a higher compression ratio. However, a cell loss or a random bit error during network transmission will permeate into the whole block, and then generate several damaged blocks. Therefore, an efficient Error Concealment (EC) scheme is essential for diminishing the impact of damaged blocks in a compressed image. In this paper, a novel adaptive EC algorithm is proposed to conceal the error for block-based image coding systems by using neural network techniques in the spatial domain. In the proposed algorithm, only the intra-frame information is used for reconstructing the image with damaged blocks. The information of pixels surrounding a damaged block is used to recover the errors using the neural network models. Computer simulation results show that the visual quality and the PSNR evaluation of a reconstructed image are significantly improved using the proposed EC algorithm.     

Error correction method based on data transformational GM(1,1) and application on tax forecasting

Accurate tax forecast is very important to carry on the macroscopic regulation efficiently under the market economy. However, experience shows that it is very difficult to improve the accuracy of forecasting by setting up a single forecasting model. This article describes the deficiencies of the present forecasting methods and puts forward a new approach to improve the accuracy of prediction by introducing error correction. First, this paper carries out initial prediction of tax revenue by using the LS-SVR model. Second, the accelerated translation transform and weighting mean value generating transform are introduced to process the error sequence. On the basis of the processed data, the error predictive method based on data transformational GM(1,1) is constructed and predicts the subsequent error. Third, the correction of preliminary prediction values is calibrated. The case study based on Chinese tax revenue during the last 30 years shows that the presented approach improves the accuracy of forecasting significantly compared with the prediction accuracy before correction, and then the validity of the model is verified.     

6DoF视频技术研究进展

随着元宇宙概念的兴起，以6自由度（six degree of freedom，6DoF）视频为代表的新一代交互式媒体技术得到产业界和学术界的广泛关注。6DoF视频隶属于多媒体通信领域，通过计算重构的方式向用户提供包括视角、光照、焦距和视场范围等多个维度的媒体交互与内容变化，能使千里之外的用户有身临其境、千人千面之感，与元宇宙具有的感知、计算、重构、协同和交互等技术特征具有高度重合性。因此，6DoF视频涵盖的技术体系可作为实现元宇宙的替代技术框架。本文提出了6DoF视频10个方面的40个问题，并将6DoF视频端到端技术链条归纳为生成、分发和呈现3个宏观阶段，随后围绕这3个技术阶段分别从内容采集与预处理、编码压缩与传输优化以及交互与呈现等方面阐述国内外研究进展。其中，在内容采集与预处理阶段，阐述了多视点联合采集、多视点与深度联合采集、深度图与点云预处理；在视频压缩与传输阶段，阐述了多视点视频编码、多视点+深度视频编码、光场图像压缩、焦栈图像压缩、点云编码压缩、6DoF视频传输优化；在交互与显示阶段，阐述了解码后滤波增强和虚拟视点合成。最后，本文围绕该领域当下的挑战，对未来趋势进行了讨论。