Research Outputs
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Publication Metadata only 3D video tools(Springer Science and Business Media Deutschland GmbH, 2019) Dumic, Emil; Boussetta, Khaled; da Silva Cruz, Luis A.; Dagiuklas, Tasos; Liotta, Antonio; Politis, Ilias; Qiao, Yuansong; Torres Vega, Maria; Ye, Yuhang; Department of Electrical and Electronics Engineering; Tekalp, Ahmet Murat; Faculty Member; Department of Electrical and Electronics Engineering; College of Engineering; 26207This chapter presents an overview of different tools used in research and engineering of 3D video delivery systems. These include software tools for 3D video compression and streaming, 3D video players, and their interfaces. Other types of tools widely used in research studies and development of new networking solutions, such as network simulators, emulators, testbeds, and network analysis tools are also covered. In addition, several 3D video evaluation tools, which have been specifically designed for testing and evaluation of 3D video sequences subject to network impairments, are further described. The chapter also presents several examples of recent works that have been carried out based on one or more simulation, emulation, test, and/or evaluation tools in research studies or innovative solutions for relevant problems affecting 3D multimedia delivery.Publication Metadata only Adaptive peer-to-peer video streaming with optimized flexible multiple description coding(IEEE, 2006) Akyol, Emrah; Department of Electrical and Electronics Engineering; Department of Electrical and Electronics Engineering; Tekalp, Ahmet Murat; Civanlar, Mehmet Reha; Faculty Member; Faculty Member; Department of Electrical and Electronics Engineering; College of Engineering; College of Engineering; 26207; 16372Efficient peer-to-peer (P2P) video streaming is a challenging task due to time-varying nature of both the number of available peers and network/channel conditions. To this effect, we propose a receiver driven P2P streaming system which utilizes a flexible scalable multiple description coding method [1], where the number of base and enhancement descriptions, and the rate and redundancy level of each description can be adapted on the fly. The optimization of the parameters of the proposed MDC scheme according to network conditions is discussed within the context of the proposed adaptive P2P streaming framework, where the number and quality of available streaming peers/paths are a priori unknown and vary in time. Experimental results, by means of NS-2 network simulation of a P2P video streaming system, show that adaptation of the number, type, and rate of descriptions and the redundancy level of each description according to network conditions yields significantly superior performance when compared to MDC schemes using a fixed number of descriptions/layers with fixed rate and redundancy level.Publication Metadata only Adaptive per-GOP bandwidth allocation for H.264 video transmission over differentiated services networks(Ieee, 2005) De Martin, JC; Department of Computer Engineering; N/A; Department of Electrical and Electronics Engineering; De Vito, Fabio; Yılmaz, Elif Merve; Tekalp, Ahmet Murat; Other; Researcher; Faculty Member; Department of Computer Engineering; Department of Electrical and Electronics Engineering; College of Engineering; Law School; College of Engineering; N/A; 267672; 26207While transmitting over differentiated services networks, in case of severe congestion also the most privileged classes may experience losses. In those cases, and especially in case of video transmission, protecting a higher fraction of traffic can have the effect of decreasing the quality, due to the overload of high-priority classes. We propose a method to compute, at source side, the allocation of video traffic over the available classes to ensure the lowest decoder-side distortion and provide traffic friendliness. To show this algorithm performance, the simple case of Poisson traffic with a bottleneck shared-buffer router is shown. The same approach can be extended to other traffic characteristics and router architectures.Publication Metadata only An optimization framework for QoS-enabled adaptive video streaming over openflow networks(Institute of Electrical and Electronics Engineers (IEEE), 2013) Civanlar, Seyhan; N/A; Department of Electrical and Electronics Engineering; Eğilmez, Hilmi Enes; Tekalp, Ahmet Murat; Master Student; Faculty Member; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; 26207OpenFlow is a programmable network protocol and associated hardware designed to effectively manage and direct traffic by decoupling control and forwarding layers of routing. This paper presents an analytical framework for optimization of forwarding decisions at the control layer to enable dynamic Quality of Service (QoS) over OpenFlow networks and discusses application of this framework to QoS-enabled streaming of scalable encoded videos with two QoS levels. We pose and solve optimization of dynamic QoS routing as a constrained shortest path problem, where we treat the base layer of scalable encoded video as a level-1 QoS flow, while the enhancement layers can be treated as level-2 QoS or best-effort flows. We provide experimental results which show that the proposed dynamic QoS framework achieves significant improvement in overall quality of streaming of scalable encoded videos under various coding configurations and network congestion scenarios.Publication Metadata only Application-layer qos fairness in wireless video scheduling(IEEE, 2006) N/A; N/A; Department of Electrical and Electronics Engineering; Department of Electrical and Electronics Engineering; Department of Electrical and Electronics Engineering; Özçelebi, Tanır; Sunay, Mehmet Oğuz; Tekalp, Ahmet Murat; Civanlar, Mehmet Reha; PhD Student; Faculty Member; Faculty Member; Faculty Member; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; College of Engineering; College of Engineering; College of Engineering; College of Engineering; N/A; N/A; 26207; 16372In mobile video transmission systems, the initial delay for pre-fetching video at the client buffer needs to be short due to buffer limitations and application-layer user convenience. Therefore, an effective cross-layer wireless design is required that considers both physical and application layer aspects of such a system. We present a cross-layer optimized multi-user video adaptation and scheduling scheme for wireless video communication, where Quality-of-Service (QoS) fairness among users is provided while maximizing user convenience and video throughput. Application and physical layer aspects are jointly optimized using a Multi-Objective Optimization (MOO) framework that tries to schedule the user with the least remaining playback time and the highest video throughput (delivered video seconds per transmission slot) with maximum video quality. Experiments with the IS-856 (1xEV-DO) standard and ITU Pedestrian A and Vehicular B environments show the improvements over today's schedulers in terms of QoS fairness and user utility.Publication Metadata only Compete or collaborate: architectures for collaborative DASH video over future networks(Ieee-Inst Electrical Electronics Engineers Inc, 2017) N/A; N/A; Department of Electrical and Electronics Engineering; Bağcı, Kadir Tolga; Şahin, Kemal Emrecan; Tekalp, Ahmet Murat; PhD Student; Master Student; Faculty Member; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; N/A; 26207Dynamic adaptive streaming over HTTP (DASH) clients compete with each other over one or more bottleneck links in a network, which results in fluctuations in TCP throughput and QoE, QoE unfairness among clients, and underutilization of the network capacity. We propose centralized and distributed architectures for collaboration between network service provider (NSP), video service provider (VSP), and users (DASH clients) to provide NSP-managed or VSP-managed DASH services over software-defined networks (SDN) with quality-of-service (QoS) reserved network slices. We show that QoS reservation alone is not sufficient to overcome QoE fluctuations per client and unfairness between heterogeneous video clients, and clients also need to employ TCP receive-window adaptation knowing their fair-share bitrate. To this effect, we propose two collaborative streaming service models to inform clients about their fair-share bitrates. We first present an NSP-managed service model with centralized collaboration between the NSP, VSP, and the users, where a traffic engineering manager at the NSP assigns a fair-share bitrate to each DASH client. We then present a VSP-managed service model with centralized or distributed collaboration architectures, where in the former the VSP determines the fair-share bitrate for each client over a reserved network slice and in the latter a group of DASH clients sharing a reserved network slice collaborate among themselves. In the novel distributed collaboration framework, collaboration groups are identified by the VSP, and clients within a group share critical parameters with each other so that each client can estimate its fair-share bitrate. Experimental results demonstrate that collaboration rather than competition between clients not only helps them achieve a smooth goodput near their fair-share bitrate, but also improves the total goodput over the reserved slice.Publication Metadata only Controlling P2P-CDN live streaming services at SDN-enabled multi-access edge datacenters(Ieee-Inst Electrical Electronics Engineers Inc, 2021) N/A; N/A; Department of Electrical and Electronics Engineering; Nacaklı, Selin; Tekalp, Ahmet Murat; PhD Student; Faculty Member; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; College of Engineering; 341857; 26207Recognizing the shortcomings of current hybrid peer-to-peer (P2P) content-distribution network (CDN) video solutions and the potential of emerging multi-access edge datacenters, we propose a novel P2P-CDN service model that is hosted at software defined networks (SDN)-enabled multi-access edge datacenters operated by network service providers (NSP). An important feature of the proposed service architecture is that both CDN access by peers and P2P video streaming between peers within edge access networks are fully controlled by cooperation of the video content provider (VCP) and NSP to optimize video service key performance indicators (KPI). The proposed fully controlled P2P-CDN architecture with P2P group formation and chunk scheduling managed at edge datacenters reduces the load on CDN servers while overcoming quality of experience (QoE) fluctuations per flow and unfairness between multiple heterogeneous video-resolution clients over reserved access network slices. Other advantages of this service include: i) better video quality and lower delay for clients; ii) better use of edge network resources; iii) avoiding illegal, unauthorized P2P content sharing. To the best of our knowledge, there are no solutions in the literature that address P2P-CDN services managed at NSP-edge datacenters combining P2P-assisted CDN, SDN-assisted edge computing, and premium service over reserved slices. Experimental results show that the proposed P2P-CDN service deployed at SDN-enabled edge datacenters provides excellent service KPI compared to other state-of-the-art solutions.Publication Metadata only Cross-layer framework for QoS support in wireless multimedia sensor networks(Institute of Electrical and Electronics Engineers (IEEE), 2012) Liang, Weifa; Department of Electrical and Electronics Engineering; N/A; Akan, Özgür Barış; Shah, Ghalib Asadullah; Faculty Member; N/A; Department of Electrical and Electronics Engineering; College of Engineering; N/A; 6647The emergence of wireless multimedia sensor networks (WMSNs) has made it possible to realize multimedia delivery on tiny sensing devices. The volume and characteristics of multimedia data is quite different from the data generated in WSNs that has raised the need to explore communication protocols for multimedia delivery in WMSNs. The existing studies focus on providing quality-of-service (QoS) to each individual source but they are not adaptive to create room for maximizing the number of sources. In this paper, we propose a novel cross-layer framework for QoS support in WMSNs. The objective of the proposed framework is to maximize the capacity of the deployed network to enhance the number of video sources given that the QoS constraint of each individual source is also preserved. This is achieved by implementing Wyner-Ziv lossy distributed source coding at the sensor node with variable group of pictures (GOP) size, exploiting multipath routing for real-time delivery and link adaptation to enhance the bandwidth under the given bit error rate. Hence, application requirements are mapped on joint operations of application, network, link and MAC layers to achieve the desired QoS. Simulation results reveal that the framework admits larger number of video sources under the satisfied distortion constraint.Publication Metadata only Delay-distortion optimization for content-adaptive video streaming(Institute of Electrical and Electronics Engineers (IEEE), 2007) N/A; N/A; Department of Electrical and Electronics Engineering; Department of Electrical and Electronics Engineering; Özçelebi, Tanır; Tekalp, Ahmet Murat; Civanlar, Mehmet Reha; PhD Student; Faculty Member; Faculty Member; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; College of Engineering; College of Engineering; N/A; 26207; 16372We propose a new pre-roll delay-distortion optimization (DDO) framework that allows determination of the minimum pre-roll delay and distortion while ensuring continuous playback for on-demand content-adaptive video streaming over limited bitrate networks. The input video is first divided into temporal segments, which are assigned a relevance weight and a maximum distortion level, called relevance-distortion policy, which may be specified by the user. The system then encodes the input video according to the specified relevance-distortion policy, whereby the optimal spatial and temporal resolutions and quantization parameters, also called encoding parameters, are selected for each temporal segment. The optimal encoding parameters are computed using a novel, multi-objective optimization formulation, where a relevance weighted distortion measure and pre-roll delay are jointly minimized under maximum allowable buffer size, continuous playback, and maximum allowable distortion constraints. The performance of the system has been demonstrated for on-demand streaming of soccer videos with substantial improvement in the weighted distortion without any increase in pre-roll delay over a very low-bitrate network using AVC/H.264 encoding.Publication Metadata only Distributed qos architectures for multimedia streaming over software defined networks(Institute of Electrical and Electronics Engineers (IEEE), 2014) Eğilmez, Hilmi E.; Department of Electrical and Electronics Engineering; Tekalp, Ahmet Murat; Faculty Member; Department of Electrical and Electronics Engineering; College of Engineering; 26207This paper presents novel QoS extensions to distributed control plane architectures for multimedia delivery over large-scale, multi-operator Software Defined Networks (SDNs). We foresee that large-scale SDNs shall be managed by a distributed control plane consisting of multiple controllers, where each controller performs optimal QoS routing within its domain and shares summarized (aggregated) QoS routing information with other domain controllers to enable inter-domain QoS routing with reduced problem dimensionality. To this effect, this paper proposes (i) topology aggregation and link summarization methods to efficiently acquire network topology and state information, (ii) a general optimization framework for flow-based end-to-end QoS provision over multi-domain networks, and (iii) two distributed control plane designs by addressing the messaging between controllers for scalable and secure inter-domain QoS routing. We apply these extensions to streaming of layered videos and compare the performance of different control planes in terms of received video quality, communication cost and memory overhead. Our experimental results show that the proposed distributed solution closely approaches the global optimum (with full network state information) and nicely scales to large networks.