Enhancing the Quality of Video Streaming Over Unreliable Wireless Networks PDF Download

Author: Muhammad Usam
Publisher:
ISBN:
Category : Digital video
Languages : en
Pages : 141

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Book Description
Real-time video transmission over unreliable wireless networks remains a serious challenge due to bandwidth limitation and sensitive nature of video bitstreams generated by todayʼs complex video encoders, e.g., High Efficiency Video Coding (HEVC/H.265). These compressed video bitsreams face packet-drop problem when transmitted over unreliable wireless networks. The effect of packet-drop on the received video quality can be minimised in two ways 1) increasing Quality of Service (QoS) by adopting efficient routing schemes between source and destination, and 2) maintaining video quality at receiverʼs side by applying smart and real-time-based Error Concealment (EC) techniques. The QoS refers to the capability of a transmission network to provide better service to selected network traffic. It is a generic term and can be applied to any data transmission network. The term video quality refers to perceived video degradation and is compared to the original video. In this dissertation, we explore the above mentioned two ways and propose a comprehensive solution for real-time video transmission over unreliable networks with the contributions as follows. 1. An efficient, lightweight and real-time EC algorithm is proposed to conceal the missing/lost video frames in H.265 encoded HD videos. The EC algorithm is based on threshold-based distributed Motion Estimation (ME) scheme and utilises only two video frames to estimate the missing one, thus eliminating the need for a large buffer and processing of a bundle of video frames to estimate the missing one. 2. Scalable video coding produces multiple interrelated bitstreams of a single video with different bitrates. For scalable bitstreams, we propose a lightweight and real-time EC algorithm to cover up the effects of missing/lost video frames. Due to complicated nature of scalable video bitstreams, our proposed EC algorithm utilises three previously processed video frames along with their master video frames to perform threshold-based distributed ME to estimate the missing video frames in enhancement layer. 3. We propose a feed-back-based on-demand multipath routing scheme over a multi-hop Wireless Multimedia Sensor Network (WMSN) to ensure the QoS. The feedback helps in deciding the optimum path between sources and destinations and reduces the Packets Loss Ratio (PLR) during the transmissions. On-demand connection assists in saving the available network resources while multipath routing aids in maintaining the connection between sources and destinations. The proposed research makes notable contributions to designing a QoS-supported HD video streaming paradigm to deliver HD videos over unreliable networks and to maintain the received video quality on resource-constrained mobile terminals.

Author: Xiaoling Qiu
Publisher:
ISBN: 9781124316062
Category :
Languages : en
Pages :

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Book Description
Wireless networks is the fundamental component of next generation communication networks to provide users ubiquitous access. Due to the flexibility provided by wireless networks, users can access the network-based information and services anytime and anywhere. However, some emerging and popular multimedia applications, like Internet Protocol television (IPTV) and Multimedia Gaming, requiring high bandwidth and small delay, pose challenge for the last-mile wireless access network. Consequently, there is significant amount of research and development efforts in enhancing the performance of multimedia applications over wireless networks. This dissertation makes four important contributions towards that end. In Chapter 2, we study the various architectures, protocols and standards to support high quality video streaming over broadband mobile networks. We survey the most popular international video coding and compression standard ISO/IEC Moving Picture Experts Group-4 (MPEG-4) or ITU-T H.264. We also survey the next generation broadband mobile LTE (Long Term Evolution) network architecture and key technologies followed by video streaming delivery architectures and network protocols supporting video streaming over broadband mobile networks. Finally, we discuss possible future direction of video streaming in wireless networks. In Chapter 3, we propose an optimization algorithm to solve the key issue of bitrate switching in next generation HTTP-based adaptive video streaming. Our solution can provide the best possible viewing quality to users without playback interruption, which is reported as the biggest concern of on-line video streaming. The optimization algorithm is based on a specific streaming architecture and it can be easily integrated with other approaches and industry standards. Simulation results show that our optimization algorithm can determine the best video bitrate according to channel condition and buffered streams in local devices to provide viewers the best possible quality with least interruption. In Chapter 4, we propose a novel architecture and mechanism to delivery high quality video to users that use a wireless mesh access network. The novel mechanism consists of 1) a network route selection scheme which provides paths for multiple video streams with the least interference, called Minimum Interference Route Selection (MIROSE) and 2) an optimization algorithm that determines the compression rates depending on the network condition, called Network State Dependent Video Compression Rate (NSDVCR) algorithm. Simulation results show that our approach can provide significant improvement of video quality measured with Peak Signal-to-noise Ratio (PSNR) compared with standard routing protocols and default compression rates. In Chapter 5, we present a novel approach to collect multiple categories of data in a resource-limited wireless sensor network. In an advanced wireless sensor network capable of sensing and collecting multiple kinds of data, it is a challenging problem to efficiently and fairly collect various critical information when network has limited resources. We propose an optimization algorithm for the buffer management in the sensor node to provide higher event throughput, and maintain coverage fidelity when network is congested. Our detailed simulation analysis show that our proposed approach has significant performance improvement with respect to event throughput, fairness and the overall value of the information collected by the wireless sensor network. The dissertation proposes and validates a number of novel mechanisms and optimization algorithms to support the most challenging multimedia application namely, video, which has the dual requirements of high-bandwidth and small-delay, in various wireless networks. We first investigate the problem of providing high-quality video streaming in broadband mobile networks. We then enhance the video quality by 1) changing the video encoding and transmission techniques so as to be suitable for the wireless network; 2) designing a novel network architecture and protocol for video streaming; and 3) jointly altering the video compression and the network transport protocol.

Author: Xiaolin Cheng
Publisher:
ISBN: 9781267758606
Category :
Languages : en
Pages :

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Book Description
As development of wireless networking technologies continues, it has been increasingly expected to support content-rich multimedia communications (e.g., video) in such networks. In this dissertation, we study the important problems of enhancing QoS support for video applications in wireless mesh networks and LTE networks. We begin our investigation with a video performance evaluation study in a wireless mesh test-bed. The goal is to clearly understand the nature of video streaming and its performance in wireless mesh networks. By extensive experiments in various scenarios we analyze the network parameters and settings which impact video performance. Compared with simulation or network-layer statistics based approaches, our investigation is directly focused on video quality in multi-hop scenarios. The experimental results better represent the characteristics of real networks and reveal the interesting aspects of video performance in mesh networks, which may benefit the design of efficient QoS solutions for multimedia services in wireless mesh networks. Next, we explore the interference issue in wireless mesh networks, and propose an interference-aware admission control and QoS routing scheme, towards enhancing video streaming experience in wireless mesh networks. Interference is characterized using a conflict graph based model. Nodes exchange their flow information periodically and compute their available residual bandwidth based on the local maximal clique constraints. Admission decision is made based on the residual bandwidth at each node. An on-demand routing scheme is implemented to explicitly incorporate the interference model in the route discovery process. By avoiding the "hot-spots" with severe interference, it discovers the routes with less interference and enhances video performance significantly. We also leverage MAC layer retransmission counts to design a combined queuing and routing scheme which achieves better video quality than the existing approaches. A case study is performed focusing on MAC layer retransmission, which helps us better understand the impacting factors on video quality in multi-hop mesh networks. Our scheme is proposed from a cross-layer perspective which leverages the information across network (routing) layer and link (MAC) layer. MAC layer retransmission count is exploited to guide the interface queue management for video packets as well as a metric to construct a retransmission-aware QoS routing scheme. In our approach, the upper layers are aware of the dynamic network status via retransmission count, so timely QoS decision can be made to enhance video quality effectively. For LTE networks, our focus is radio resource management. We first investigate the important problem of downlink resource allocation in recently enhanced LTE-Advanced systems where a newly added feature, carrier aggregation, provides more flexibility in resource allocation in addition to the existing resource block level packet scheduling. The resource allocation problem is formulated as a complex combinatorial problem with multiple constraints. We decompose this highly complex optimization problem and construct a two-tier resource allocation framework which incorporates dynamic component carrier assignment and novel backlog based scheduling schemes with intelligent link adaptation based on weighted CQI. The proposed schemes offer both better throughput and delay performance as well as user fairness. Finally, we address the downlink scheduling problem in LTE networks by directly optimizing video quality. Unlike the conventional scheduling rules which exploit network layer metrics, our scheme is directly targeted on optimizing application-layer video quality. Video quality optimized scheduling is formulated as a complex combinatorial optimization problem, and solved by exploiting a GA (genetic algorithm) based metaheuristic approach. The intrinsic strength of population based solution of GA offers a superior advantage for this type of scheduling problems. Simulation results demonstrate the effectiveness of GA based scheduling scheme compared with the well-known M-LWDF scheduling rule and the simulated annealing method. It can offer better video quality at the receiver within the required delay bound.

Author: Wei Chen
Publisher:
ISBN: 9781369681208
Category :
Languages : en
Pages : 127

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Book Description
With the popularity of and the advances in wireless networking technologies, wireless multimedia tra c has grown dramatically in recent years. Despite having many advantages, wireless multimedia services, particularly video services, still pose a number of challenges due to the time-varying, error-prone and bandwidth-fluctuating channels in the wireless networks. Therefore, provisioning end-to-end Quality of Service and Quality of Experience (QoS and QoE) of video transmission over wireless channels is of great importance. ☐ Video transmission is often described to be bursty as video is basically a sequence of frames transmitted at a particular frame rate. A video frame cannot be decoded or played out at the receiver side until all or most of its transmitted constituent packets are received in time. Depending on the application scenarios, video services may have different emphases in terms of QoE and QoS. While video streaming (e.g., Netflix and YouTube) allows for modest delay (on the order of a few seconds) at the beginning of the playout, video teleconferencing (e.g., FaceTime and WebRTC) is much more delay constrained (less than a few hundred milliseconds). This is because in real-time video systems, each frame must be delivered and decoded by its playback time, and any packet that is retransmitted due to loss in the last transmission or arriving late becomes useless when its stringent decoding and display deadline cannot be met. In this dissertation, we propose several optimization algorithms to improve the QoE and QoS for both video streaming (non real-time) and video teleconferencing (real-time) over wireless networks. ☐ In optimizing wireless video streaming, we focus on MPEG-DASH (ISO/IEC Standard 23009-1), the current standard for video streaming. We optimize video streaming by leveraging a technique called User Adaptive Video (UAV), which exploits the perceptual limits of the human visual system to modulate a video stream’s bit rate based on the viewing conditions, such as viewing distance and ambient illuminance, resulting in significant bandwidth saving without perceived loss of quality to the user. UAV presents an opportunity to significantly improve the e ciency of DASH by not requesting unnecessarily high bit rate videos. We design UAV-enabled DASH (UDASH) and evaluate its performance in Wi-Fi networks. Simulation results show that UDASH in a Wi-Fi network has the benefits of not only significantly improving the video streaming performance such as reducing the rebu ering probability, but also enhancing the performance of cross traffc. ☐ In addition, the MPEG-DASH standard uses TCP as the underlying transport layer protocol, and more importantly, TCP is one type of dominant tra c in the Internet. Therefore, we investigate how to improve TCP performance in wireless networks. We identify two issues of TCP performance degradation due to common channel errors via both analytical study and simulations in a typical Wi-Fi network. Motivated by these issues, a MAC layer optimization technique is proposed, which is based on the adaptation of the Retry Limit parameter after considering TCP traffic characteristics and throughput model. The evaluation results confirm that the proposed technique achieves higher performance gain. ☐ In optimizing video teleconferencing, we considerWebRTC, which is Google’s open source real-time communication framework. In wireless networks such as those based on IEEE 802.11, packet losses due to fading and interference are often misinterpreted as indications of congestion, causing unnecessary decrease in the data sending rate due to congestion control by the RTCP protocol working beneath WebRTC and above RTP. For delayconstrained applications such as video teleconferencing, packet losses may result in excessive artifacts or freeze in the decoded video. We propose a simple and yet effective mechanism to detect and reduce channel-caused packet losses by dynamically adjusting the retry limit parameter of the IEEE 802.11 protocol. Since the retry limit is left configurable in the IEEE 802.11 standard, and does not require cross-layer coordination, the proposed scheme can be easily implemented and incrementally deployed. We also propose to use a delay constrained retry limit adaptation algorithm to control transmission delays so that delay constraints required by different application scenarios can be met. Experimental results of applying the proposed scheme to aWebRTC based real-time video communication prototype show significant performance gain compared to the case where retry limit is configured statically. ☐ In addition to the optimization techniques proposed for the IEEE 802.11 protocol, we also propose a cross-layer approach to optimize video teleconferencing, termed early packet loss feedback (EPLF). In EPLF, if a packet loss is due to channel errors, the MAC layer directly feeds back the loss information to the RTP layer with a spoofed RTCP packet that carries a NACK message so that the RTP layer can retransmit the lost RTP packet. Since the whole feedback process takes place in the same device (the video sender), the latency is negligible in relation to the RTT, and hence the term ’early’ in EPLF. Theoretical analysis and prototype-based experimental results show that EPLF almost completely eliminates channelcaused video freezes in the decoded video while improving congestion control. ☐ Furthermore, we also apply the technique of UAV to video teleconferencing to further reduce bandwidth consumption, and build a prototype based on WebRTC and Licode (a video teleconferencing hub platform) to validate the bandwidth savings.

Author:
Publisher:
ISBN:
Category : Dissertations, Academic
Languages : en
Pages : 73

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Book Description
There is an increased awareness on security everywhere and the use of wireless internet technologies for security and surveillance applications is increasing. The Surveillance applications vary from monitoring super markets to large coast line harbors and so on. The solutions currently available in the market are proprietary, expensive and very hard to deploy. The objective of this project is to overcome this complexity and to come up with a simple and scalable solution to stream video wirelessly using open source software and easily available devices. The recent trend in multimedia computing applications requires increasing bandwidth and computing power. As an integral part of multimedia computing, the efficiency of digital video processing is a very compelling issue. This research focuses on an efficient way to wirelessly stream video from any Standard video4linux compatible USB Web Camera which can be scaled to high-end surveillance cameras as well to a mobile user. All communication between the mobile user and the web camera will be performed using a web browser. A real-time video stream will be efficiently encoded and transmitted from the web camera over an 802.11 WLAN and displayed in a mobile user's browser. In this project the end users will be able to remotely view the live video stream using any standard web browser running on any device with a wired or wireless interface. We have proposed a novel video encoding scheme to efficiently transmit video frames to a remote browser. Based on link quality and signal strength, the web camera will adaptively modify the number of frames transmitted per second and the quality of a transmitted frame to reduce packet loss and efficiently saving bandwidth and present the end user with a glitch free video. Based on the available bit rate information and the pre-determined data model the rate-adaptation module uses 'Newton Raphson' method to determine the encoding parameters. The research also includes understanding of various video compression techniques and Real time video streaming methods. Understanding of some open source libraries such as FFmpeg, MPEG4IP and Live555 are also a part of the research.

Author: Eric Setton
Publisher: Springer Science & Business Media
ISBN: 0387741143
Category : Computers
Languages : en
Pages : 157

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Book Description
The book describes novel solutions to enhance video quality, increase robustness to errors, and reduce end-to-end latency in video streaming systems. The authors are leading Researchers from Stanford University.

Author: Yang Xiao
Publisher: CRC Press
ISBN: 1420060473
Category : Computers
Languages : en
Pages : 440

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Book Description
Advances in the area of wireless and mobile telemedicine to diagnose and treat patients have drawn growing attention from healthcare providers and recipients, industry, researchers, and governments.This volumeexamines computing and network dilemmas which arise from wireless and mobile telemedicine. Comprised of the contributions of many prominent international researchers, the book gives an overview of patient care and monitoring, discusses the use of telemedicine in cardiology and diabetes, analyzes security and privacy considerations, examines issues relating to networking support, and concludes with a section on the opportunities and challenges that are faced by those involved in this exciting technology.

Author: Kai Dong
Publisher:
ISBN:
Category : HTTP (Computer network protocol)
Languages : en
Pages : 105

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Book Description
With the development of the Internet and mobile networks, video service in mobile devices has gained growing popularity. Guaranteeing a decent video service quality is, however, still quite challenging in wireless networks, due to the unstable features of radio channels. In this thesis, we investigate simulation and enhancement of video services based on the hypertext transfer protocol (HTTP) with adaptive streaming over wireless networks. Firstly, we implement a video service simulator to explore video quality monitoring and collection of performance metrics during content delivery. Then, we further propose a caching-based bitrate adaptation scheme for the purpose of video service quality enhancement. Instead of focusing on the traditional quality of service (QoS), we use a quality of experience (QoE) model for video performance evaluation. A series of experiments are conducted to assess the performance of our proposed bitrate adaptation scheme and compare it with several existing representative adaptation schemes. Experiments demonstrate that our proposed adaptation scheme outperforms the reference schemes by achieving higher mean opinion scores (MOS) as the QoE measure in a variety of network conditions.

Author: Guang Ji
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description

Author: Sebastian Möller
Publisher: Springer
ISBN: 331902681X
Category : Technology & Engineering
Languages : en
Pages : 431

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Book Description
This pioneering book develops definitions and concepts related to Quality of Experience in the context of multimedia- and telecommunications-related applications, systems and services and applies these to various fields of communication and media technologies. The editors bring together numerous key-protagonists of the new discipline “Quality of Experience” and combine the state-of-the-art knowledge in one single volume.