Channel adaptive video stream switching for broadband wireless links

This paper exploits an H.264/Advanced Video Coding codec’s smooth stream switching to achieve robust video delivery across an IEEE 802.16 (WiMAX) broadband wireless link. As the wireless channel conditions vary over time, dynamic selection of bitrate and corresponding video quality will reduce the risk of harmful packet loss. The paper investigates choice of stream-switching with Secondary SP-frames or SI-frames relative to the selection of quantization parameter (QP) values. To control the switching points at the WiMAX server, the proposed scheme applies a feedback mechanism that monitors packet loss. As an additional suggestion, the paper considers an adaptive ARQ scheme to protect switching frames against packet loss. In summary, the broadband wireless streaming system gives more protection to higher quality video, reduces delay and packet loss, and improves received video quality. In particular, for the QP values selected, results show that increased quality primary-switching frames together with SI frames bring a significant gain in video quality compared with other switching schemes with secondary SP-frames. The other schemes in turn show an improvement to using ‘no switching’ when streaming takes place over a typical WiMAX channel with burst errors. Link delay is also reduced.     

Video streaming distribution over mobile Internet: a survey

In recent times, mobile Internet has witnessed the explosive growth of video applications, embracing user-generated content, Internet Protocol television (IPTV), live streaming, video-on-demand, video conferencing, and FaceTime-like video communications. The exponential rise of video traffic and dynamic user behaviors have proved to be a major challenge to video resource sharing and delivery in the mobile environment. In this article, we present a survey of state-of-the-art video distribution solutions over the Internet. We first discuss the challenges of mobile peer-to-peer (MP2P)-based solutions and categorize them into two groups. We discuss the design idea, characteristics, and drawbacks of solutions in each group.We also give a reviewfor solutions of video transmission in wireless heterogeneous networks. Furthermore, we summarize the information-centric networking (ICN)-based video solutions in terms of in-network caching and name-based routing. Finally, we outline the open issues for mobile video systems that require further studies.     

Wireless CDN video streaming architecture for IPTV

Wireless IPTV (Internet Protocol TeleVision) aims to make the traditional IPTV and related services available to users anywhere, anytime, on any device, and through any network. Mobile streaming TV is one of the alternatives to deploy such a system; others are DVB-H or MediaFLO. In this paper we propose an alternative CDN-based architecture to distribute contents to different access networks, in order to create a triple screen platform. The core elements of the system are the video streamers, acting as surrogates of the mobile CDN-based architecture, installed in the access networks (including mobile), and the transcoding servers in the premises of the content providers. The paper focused on the wireless part of the system, analyzing the architecture and performance results related with the video coding and the efficiency obtained due to the placement of the streaming servers. The system has been deployed by a Spanish media company for its use with different Telcos, ISPs and media companies.     

A Quality-Driven Cross-Layer Solution for MPEG Video Streaming Over WiMAX Networks

Extensive efforts have been focused on deploying broadband wireless networks. Providing mobile users with high speed network connectivity will let them run various multimedia applications on their wireless devices. Satisfying users with different quality-of-service requirements while optimizing resource allocation is a challenging problem. In this paper, we discuss the challenges and possible solutions for transmitting MPEG video streams over WiMAX networks. We will briefly describe the MPEG traffic model suggested by the WiMAX Forum. A cross-layer solution for enhancing the performance of WiMAX networks with respect to MPEG video streaming applications is explained. Our solution uses the characteristics of MPEG traffic to give priority to the more important frames and protect them against dropping. Besides, it is simple and compatible with the IEEE 802.16 standards and thus easily deployable. It is shown that the proposed solutions will improve the video quality over WiMAX networks.     

EPON＋EOC技术在有线电视网络改造中的应用

随着科学技术的发展和信息化时代的到来,有线电视网络己经成为我国信息化基础设施的重要组成部分,但IPTV、直播卫星、移动电视和网络流媒体等的出现使广电有线广播电视网络遭遇前所未有的冲击,直接威胁到广电有线广播电视网络的生存和发展。     

IPTV service based on a content-zapping paradigm

Internet protocol television (IPTV) generically designates a real-time distribution service for multimedia contents over an IP network, such as the Internet. There are many advantages of IPTV deployment over current digital or air broadcast TV signals: integration, the use of the switched internet protocol (IP), the possibility to build home networks that can be used to share multimedia contents over different devices, the easy implementation of video on demand services and the usage of better compression and encryption standards. In order to implement this kind of service, it is extremely useful to have a system that can efficiently classify multimedia contents and users and distribute them in a customized way. This paper proposes a novel IPTV service for the distribution of personalized multimedia contents over IP networks based on the concept of content-zapping, in contrast to traditional channel-zapping: each client system receives a multimedia streaming that is automatically composed by the system based on the user preferences and the user will only interact with the system by requesting a content change or marking a content as favorite. The paper will describe the general functionality of the service and will present the detailed architecture of the IPTV server, the key component of the service infrastructure. The server must maintain a list of media contents residing in other systems and must keep a dynamic classification of the multimedia contents that are stored in its database. This classification is built and gradually refined based on the interactions between clients and multimedia contents. Special attention is given in the paper to the classification model, describing the general ideas that are used to automatically suggest multimedia contents to a specific user (that is characterized by his complete profile). A specific content may be suggested to the user based on the knowledge of the user profile and/or based on specific and dynamic information, such as the user position, the local temperature, date and time. The availability of this information obviously depends on the specific user device that is being used. The proposed system allows any client device to connect, allowing a high level of interoperability. It is also possible to use all the device capabilities and sensors, like Global Positioning System (GPS), accelerometers, light sensors, noise sensors, etc., thus creating a context environment that helps classify each user profile. These context-awareness mechanisms applied to mobile devices with wireless network (802.11b/g/n, WiMAX, GSM, UMTS, etc.) capabilities allow a better user experience and more accurate multimedia suggestions, due to the deep knowledge about the user device, network and environment. The system also allows the users to suggest contents to other users in the same “group of friends”. Several performance tests were already conducted and the results obtained show that the proposed system is very stable and fast, even for high increases on the number of users.     

基于流媒体相关的视频安全组播协议(MSMP)研究

随着无线网络的快速发展和Internet中流媒体视频的巨大成功,无线网络中的视频服务有望在不久的将来得到大规模部署,无线网络上的实时流媒体传输技术已成为研究热点,而其中视频安全组播协议是一个关键问题。但是,由于无线网络中有限的带宽和有限的存储空间,外部的攻击与自适应机制带来的安全性问题在无线流媒体视频中是不可避免的。一个精心设计的密钥管理算法不仅可以明显地提高流媒体视频的性能,还能够保证可靠的数据嵌入以及实时视频应用提供安全支持。如何设计一个高效的密钥管理算法,是当前流媒体视频应用中一个备受关注的问题。针对无线视频应用,针对一个处于开放和不安全的网络环境中的自适应视频应用的密钥管理算法进行了研究,并进行了算法评价。     

面向移动网络的实时视频转码系统

针对宽带IPTV视频源向移动网络和移动终端提供视频服务需要解决的视频转码问题,设计开发以软件方式实现的实时视频转码系统,可将MPEG-4格式的高码率、高分辨率节目源实时转换为适合移动网络和移动终端的低码率、低分辨率视频。在误差补偿转码框架的基础上,提出一种自适应的转码时延保证方法,解决了转码计算复杂性和转码质量均衡的关键技术问题,保证了转码系统的实时性。测试结果表明,实现的转码系统视频转换质量损失少、实时性高。     

无线局域网视频流组播优化机制

针对网络电视业务的802.11无线局域网数据传输问题,提出一种视频流组播优化机制,基于视频帧区分的方法,对关键帧I帧采用可靠组播机制传输,对非关键的B帧和P帧采用组播机制传输。仿真结果表明,该机制可以在丢帧率和数据延迟之间取得较好的折中,尤其是在无线网络带宽不足的情况下,能够有效提高数据传输后视频的观看质量。     

A novel prebuffering scheme for IPTV service

The Internet Protocol TeleVision (IPTV) network utilizes the broadband IP network to provide users the TV service. Due to the limited bandwidth of the IP network, IPTV does not broadcast the content of all channels to its users. The channel zapping time (i.e., the delay between the time when the user switches to a new TV channel and the time when the content of the new TV channel is received by the user) and content miss (i.e., the content of the new TV channel arrives after the user switches to another TV channel so that the user did not watch the content of the new TV channel) significantly affect the QoS of IPTV service. This paper proposes Dynamic Prebuffering Scheme (DPS) that dynamically prebuffers the content of TV channels in the Home Gateways (HGs) based on the user’s behavior to reduce the channel zapping time and the content miss probability. A prebuffer timer is implemented in DPS to reduce the bandwidth consumption. Both the analytic model and simulation experiments are developed to investigate the performance of DPS. The simulation results show that the performance enhancements are bounded by the setup of the number of prebuffering channels and the prebuffer timer. Based on the performance study, the IPTV operators can properly set the number of prebuffered channels and the prebuffer timer to obtain good performance. Our study indicates that DPS can significantly reduce the channel zapping time and the content miss probability by slightly increasing bandwidth consumption.     

The broadband revolution

The broadband revolution truly is of the same magnitude as the industrial revolution of the 1800s. The changes we're going to see over the next decade will principally come from the connected home. We'll see bandwidth increasing a thousandfold from today's voice band 56-Kbps modems to tens of megabits per second through DSL and cable modems, and other satellite and wireless technologies. To have an impact on the millions of people who do not have computers, we'll need to turn the television set into a medium that somewhat simulates what they would now get with a computer and add fully interactive video at broadband speeds. The future connected home will have numerous service providers sending a broad pipe to the home over satellite, cable, DSL, or terrestrial wireless. It doesn't matter how we connect the home; we'll see a broadband gateway in the home, much like today's office that has a broadband router connected to the Internet. The connected environment doesn't necessarily have to be wired, but cable and phone lines are a natural choice, especially in the US, and will be first to market with the widest deployment. There will be no rewiring; clearly if we have to rewire, we'll never have a market. We'll also need wireless mobile connectivity within the home for all the devices we'll use. The telephones will be converted to Internet videophones, and MPEG video will be delivered over the Internet. As we are well aware, the TV set is being upgraded substantially. Certainly the HDTV format with the 16 x 9 aspect ratio and high resolution display will finally allow us to read Web pages on the TV set in a reasonable format. We'll have fancy on-screen displays and videophone pop-up screens with a TV camera sitting on the TV set so we can make video calls to Grandma     

Zebroid: using IPTV data to support STB-assisted VoD content delivery

IPTV, unlike Internet TV, delivers digital TV and multimedia services over IP-based networks with the required level of quality of service (QoS) and quality of experience (QoE). Linear programming channels in IPTV are delivered through multicast, which is highly scalable with the number of subscribers. Video-on-demand (VoD) content, on the other hand, is typically delivered using unicast, which places a heavy load on the VoD servers and all the network components leading to the end-user set-top boxes (STBs) as the demand increases. With the rapid growth of IPTV subscribers and the shift in video viewing habits, the need to efficiently disseminate large volumes of VoD content has prompted IPTV service providers to consider the use of STBs to assist in video content delivery. This paper describes our current research work on Zebroid, a potential VoD solution for fiber-to-the-node (FTTN) networks, which uses IPTV data on a recurring basis to determine how to select, stripe, and preposition popular content in selected STBs during idle hours. A STB requesting VoD content during the peak hours can then receive necessary stripes from participating STBs in the neighborhood. Recent VoD request access patterns, STB availability data, and capacity data on network components are taken into consideration in determining the parameters used in the striping algorithm of Zebroid. We show both by simulation and emulation on a realistic IPTV testbed that the VoD server load can be reduced by more than 70% during peak hours by allocating only 8 GB of storage on each STB. The savings achieved through Zebroid would also allow IPTV service providers to add more linear programming channels without expensive infrastructure upgrades.     

An efficient hybrid push-pull methodology for peer-to-peer video live streaming system on mobile broadcasting social media

With the rapid growth of wireless communication technology, the availability of highly flexible and video-friendly mobile terminal platforms (such as smartphones and tablets), the emergence of major video content providers (like YouTube, Ustream, and PPTV, which provide a large catalog of attractive contents), Peer-to-Peer (P2P) live video streaming over the wireless and Internet is becoming more and more attractive to users. One of the main challenges is to provide a good quality of service though the dynamic behavior of the network. Traditionally, tree-based model uses a push method, that broadcaster transfers data to other users. This model has low start-up delay. However, there are two main problems in this method: if the bandwidth of an internal node is low, children nodes may lose data and when an internal node failure, other nodes can’t receive data until completing the recovery of the tree. On the other hand, mesh-based model uses a pull method, has low bandwidth of a neighbor node by pulling necessary data from a number of neighbor nodes. However, mesh-based model requires large buffers to support pull data from neighbor peers and there is an adjustment between minimum delay by sending pull request and overhead of whole system. So, both models have their own strengths and weaknesses. This paper proposes a new hybrid push-pull live P2P video streaming protocol called MobileCast that combines the benefits of pull and push mechanisms for live video delivery. We present new topology for P2P network with more stable and provide better video streaming quality. Our main goal is to minimize the network end-to-end delay, startup time, overhead, packet loss compared to the pure mesh networks, pure tree networks and provide a good quality of service though the dynamic behavior of the network.

     

基于端系统的视频流组播速率控制方法

针对目前Internet未对多媒体应用提供QoS保障的问题,分析了视频流组播的难点,提出了一种基于缓冲区管理的网络自适应组播发送速率控制方法.该机制可以合理控制服务器的发送速率,既能自适应网络状况的变化,又满足流媒体实时播放的需求.实验结果表明,该机制通过控制发送缓冲区占有率,降低了分组丢包率,提高了终端的接收质量,具有良好的实用价值.     

Personalized and mobile digital TV applications

The introduction of mobile and broadband networks in complement to the existing satellite, cable, and terrestrial platforms, opens new opportunities for interactive TV (ITV) applications. In addition, the widespread adoption of multimedia computing has enabled the processing of TV content on personal devices such as mobile phones and PCs. The above developments raise novel issues and require the adoption of new multimedia standards and application frameworks. In particular, the explosion in the amount of available TV channels over digital television platforms (broadcast or internet protocol) makes searching and locating interesting content a cumbersome task. In this context, personalization research is concerned with the adaptation of content (e.g. movies, news, advertisements). Personalization is achieved with the employment of algorithms and data collection schemes that predict and recommend to television viewers content that match their interests. In addition, the distribution of TV content to mobile devices over broadband wireless raises the issue of video quality. Video quality depends on many aspects of the video encoding systems, such as bit rate and algorithms that model human perception of video on small screens. In this article, we examine contemporary research in personalized and mobile digital TV applications. Moreover, we present a critical survey of the most prominent research and provide directions for further research in personalized and mobile digital TV (DTV) applications.     

CStream: neighborhood bandwidth aggregation for better video streaming

Despite the popularity of watching videos online, challenges still remain in video streaming in many scenarios. Limited home broadband and mobile phone 3G bandwidths mean many users stream videos at compromised quality. To provide additional bandwidth for streaming, we propose CStream, a system that aggregates bandwidth from multiple cooperating users in a neighborhood environment for better video streaming. CStream exploits the fact that wireless devices have multiple network interfaces and connects cooperating users with a wireless ad-hoc network to aggregate their unused downlink Internet bandwidth. CStream dynamically generates a streaming plan to stream a single video using multiple connections, continuously adapting to changes in the neighborhood and variations in the available bandwidth. CStream is developed and evaluated on a test bed of computers, allowing for a detailed, controlled evaluation of performance. Analysis of the results shows a linear increase in throughput over single-connection streaming and improved video quality as the number of cooperating users in a neighborhood increase.     

A network algorithm for 3D/2D IPTV distribution using WiMAX and WLAN technologies

The appearance of new broadband wireless technologies jointly with the ability to offer enough quality of service to provide IPTV over them, have made possible the mobility and ubiquity of any type of device to access the IPTV network. The minimum bandwidth required in the access network to provide appropriate quality 3D/2D IPTV services jointly with the need to guarantee the Quality of Experience (QoE) to the end user, makes the need of algorithms that should be able to combine different wireless standards and technologies. In this paper, we propose a network algorithm that manages the IPTV access network and decides which type of wireless technology the customers should connect with when using multiband devices, depending on the requirements of the IPTV client device, the available networks, and some network parameters (such as the number of loss packets and packet delay), to provide the maximum QoE to the customer. The measurements taken in a real environment from several wireless networks allow us to know the performance of the proposed system when it selects each one of them. The measurements taken from a test bench demonstrate the success of our system.     

基于无线网络环境下的移动流媒体系统的实现

随着现在无线网络质量的提高。以及终端增值业务的不断发展．通过终端实现收看电视节目、以及实现远程监控和电话会议将会成为最能吸引用户的业务．本文基于现有的无线网络环境．结合当前的图像压缩技术H．263与MPEG4，围绕如何建设流媒体平台．给出了其组网和系统集成方案。并对流媒体系统的内容管理、业务管理、计费管理做了论述。     

Multipoint-to-point communications for SHE surveillance with QoS and QoE management

The bandwidth-hunger applications of SHE (Smart Home Environment) can take advantage of the multipoint-to-point (MPP) connections to aggregate more bandwidth to gain user-perceived Quality of Experience (QoE) and network Quality of Service (QoS). The receiver-centric transport-layer R²CP (Radial Reception Control Protocol) was proposed to resolve the incapability of the MPP communication in conventional TCP and UDP. However, R²CP has no consideration to discriminate the importance in a packet payload which is critical to QoE and brings an issue for critical data packets that may be dropped in great risk of network congestion. In this paper, we thus present P-R²CP (Prioritized R²CP) to effectively decrease the loss ratio of critical data packets in MPP video streaming while the network is congested. P-R²CP is a cross-layer protocol that considers both the transport-layer issues and the media content’s properties in application-layer. Then, an example on MPP-UVS (MPP ubiquitous video surveillance) is presented as UVS is now a very important Internet application that requires QoS/QoE management to protect lives and assets especially in SHE. Our experiments are conducted on different kinds of surveillance videos over MPP links with different bandwidth and packet loss inserted. The experimental results demonstrate that, as the loss of critical packets is decreased by an order and much less critical data packets are dropped, P-R²CP can highly guard not only QoS but also QoE of SHE surveillance video streaming.     

Multiple TFRC Connections Based Rate Control for Wireless Networks

Rate control is an important issue in video streaming applications for both wired and wireless networks. A widely accepted rate control method in wired networks is equation based rate control , in which the TCP friendly rate is determined as a function of packet loss rate, round trip time and packet size. This approach, also known as TCP friendly rate control (TFRC), assumes that packet loss in wired networks is primarily due to congestion, and as such is not applicable to wireless networks in which the bulk of packet loss is due to error at the physical layer. In this paper, we propose multiple TFRC connections as an end-to-end rate control solution for wireless video streaming. We show that this approach not only avoids modifications to the network infrastructure or network protocol, but also results in full utilization of the wireless channel. NS-2 simulations, actual experiments over 1$times$RTT CDMA wireless data network, and and video streaming simulations using traces from the actual experiments, are carried out to validate, and characterize the performance of our proposed approach.