QoS adaptation in multimedia multicast conference applications for e-learning services

Tolerant real-time applications, such as video conferences, are in the frontline to benefit from QoS adaptation. However, not all include adaptive technology able to provide both end-system and network quality awareness. Adaptation, in these cases, can be achieved by introducing a multiplatform middleware layer responsible for tutoring the applications’ resources (enabling adjudication or limitation) based on the available processing and networking capabilities. Congregating these technological contributions, an adaptive platform has been developed integrating public domain multicast tools, applied to a Web-based distance learning system. The system is user-centered (estudent), aiming at good pedagogical practices and proactive usability for multimedia and networkresources. The services provided, including QoS adapted interactive multimedia multicast conferences (MMC), are fully integrated and transparent to end-users. QoS adaptation, when treated systematically in tolerant real-time applications, denotes advantages in group scalability and QoS sustainability in heterogeneous and unpredictable environments such as the Internet

Quality-adaptive media streaming

Thesis (Master)--Izmir Institute of Technology, Computer Engineering, Izmir, 2012Includes bibliographical references (leaves: 37-40)Text in English; Abstract: Turkish and Englishxi, 40 leavesIn this study, an adaptive method for maximizing network bandwidth utilization for real-time media streaming applications is presented. The proposed method implements a rate control approach over the transport protocol RTP. RTP is coupled with an existing multimedia codec, H.264. A controller that keeps the RTP packet loss fraction at a predefined reference point is implemented. During the course of the stream transmission, the information about the network state is generated by the RTP/RTCP and sent to the server by the clients. Packet loss fraction parameter is fed into the controller. Controlling the multimedia codec bitrate directly affects the packet transmission rate, therefore RTP packet transmission rate is also controlled. Two control approaches are proposed. Firstly, a PID controller is introduced. This PID controller is designed without any self adaptation and manually tuned to maximize all of the available bandwidth. Secondly, a model reference adaptive controller (MRAC) is proposed. This MRAC controller constantly adjusts its parameters according to a reference model. The output of the TCP Friendly Rate Control Algorithm (TFRC) is used as the model to keep the MRAC controller friendly towards other flows flows at a level that the application requires. Simulations are provided to demonstrate the operation of the proposed methods. In the simulations, a content streaming scenario is run against background traffic for the available bandwidth in a bottleneck network configuration

Multimedia transmission with adaptive QoS based on real-time protocols

this paper, we describe a mechanism for adaptive transmission of multimedia data, which is based on real-time protocols. The proposed mechanism can be used for unicast or multicast transmission of multimedia data over heterogeneous networks, like the Internet, and has the capability to adapt the transmission of the multimedia data to network changes. In addition, the implemented mechanism uses an inter-receiver fairness function in order to treat the group of clients with fairness during the multicast transmission in a heterogeneous environment. The proposed mechanism uses a `friendly' to the network users congestion control policy to control the transmission of the multimedia data. We implement a prototype application based on the proposed mechanism and we evaluate the proposed mechanism both in unicast and multicast transmission through a number of experiment and a number of simulations in order to examine its fairness to a group of clients and its behaviour against transport protocols (TCP) and UDP data streams. Copyright # 2003 John Wiley & Sons, Lt

Real-time communications over switched Ethernet supporting dynamic QoS management

Doutoramento em Engenharia InformáticaDurante a última década temos assistido a um crescente aumento na utilização de sistemas embutidos para suporte ao controlo de processos, de sistemas robóticos, de sistemas de transportes e veículos e até de sistemas domóticos e eletrodomésticos. Muitas destas aplicações são críticas em termos de segurança de pessoas e bens e requerem um alto nível de determinismo com respeito aos instantes de execução das respectivas tarefas. Além disso, a implantação destes sistemas pode estar sujeita a limitações estruturais, exigindo ou beneficiando de uma configuração distribuída, com vários subsistemas computacionais espacialmente separados. Estes subsistemas, apesar de espacialmente separados, são cooperativos e dependem de uma infraestrutura de comunicação para atingir os objectivos da aplicação e, por consequência, também as transacções efectuadas nesta infraestrutura estão sujeitas às restrições temporais definidas pela aplicação. As aplicações que executam nestes sistemas distribuídos, chamados networked embedded systems (NES), podem ser altamente complexas e heterogéneas, envolvendo diferentes tipos de interacções com diferentes requisitos e propriedades. Um exemplo desta heterogeneidade é o modelo de activação da comunicação entre os subsistemas que pode ser desencadeada periodicamente de acordo com uma base de tempo global (time-triggered), como sejam os fluxos de sistemas de controlo distribuído, ou ainda ser desencadeada como consequência de eventos assíncronos da aplicação (event-triggered). Independentemente das características do tráfego ou do seu modelo de activação, é de extrema importância que a plataforma de comunicações disponibilize as garantias de cumprimento dos requisitos da aplicação ao mesmo tempo que proporciona uma integração simples dos vários tipos de tráfego. Uma outra propriedade que está a emergir e a ganhar importância no seio dos NES é a flexibilidade. Esta propiedade é realçada pela necessidade de reduzir os custos de instalação, manutenção e operação dos sistemas. Neste sentido, o sistema é dotado da capacidade para adaptar o serviço fornecido à aplicação aos respectivos requisitos instantâneos, acompanhando a evolução do sistema e proporcionando uma melhor e mais racional utilização dos recursos disponíveis. No entanto, maior flexibilidade operacional é igualmente sinónimo de maior complexidade derivada da necessidade de efectuar a alocação dinâmica dos recursos, acabando também por consumir recursos adicionais no sistema. A possibilidade de modificar dinâmicamente as caracteristicas do sistema também acarreta uma maior complexidade na fase de desenho e especificação. O aumento do número de graus de liberdade suportados faz aumentar o espaço de estados do sistema, dificultando a uma pre-análise. No sentido de conter o aumento de complexidade são necessários modelos que representem a dinâmica do sistema e proporcionem uma gestão optimizada e justa dos recursos com base em parâmetros de qualidade de serviço (QdS). É nossa tese que as propriedades de flexibilidade, pontualidade e gestão dinâmica de QdS podem ser integradas numa rede switched Ethernet (SE), tirando partido do baixo custo, alta largura de banda e fácil implantação. Nesta dissertação é proposto um protocolo, Flexible Time-Triggered communication over Switched Ethernet (FTT-SE), que suporta as propriedades desejadas e que ultrapassa as limitações das redes SE para aplicações de tempo-real tais como a utilização de filas FIFO, a existência de poucos níveis de prioridade e a pouca capacidade de gestão individualizada dos fluxos. O protocolo baseia-se no paradigma FTT, que genericamente define a arquitectura de uma pilha protocolar sobre o acesso ao meio de uma rede partilhada, impondo desta forma determinismo temporal, juntamente com a capacidade para reconfiguração e adaptação dinâmica da rede. São ainda apresentados vários modelos de distribuição da largura de banda da rede de acordo com o nível de QdS especificado por cada serviço utilizador da rede. Esta dissertação expõe a motivação para a criação do protocolo FTT-SE, apresenta uma descrição do mesmo, bem como a análise de algumas das suas propiedades mais relevantes. São ainda apresentados e comparados modelos de distribuição da QdS. Finalmente, são apresentados dois casos de aplicações que sustentam a validade da tese acima mencionada.During the last decade we have witnessed a massive deployment of embedded systems on a wide applications range, from industrial automation to process control, avionics, cars or even robotics. Many of these applications have an inherently high level of criticality, having to perform tasks within tight temporal constraints. Additionally, the configuration of such systems is often distributed, with several computing nodes that rely on a communication infrastructure to cooperate and achieve the application global goals. Therefore, the communications are also subject to the same temporal constraints set by the application requirements. Many applications relying on such networked embedded systems (NES) are complex and heterogeneous, comprehending different activities with different requirements and properties. For example, the communication between subsystems may follow a strict temporal synchronization with respect to a global time-base (time-triggered), like in a distributed feedback control loop, or it may be issued asynchronously upon the occurrence of events (eventtriggered). Regardless of the traffic characteristics and its activation model, it is of paramount importance having a communication framework that provides seamless integration of heterogeneous traffic sources while guaranteeing the application requirements. Another property that has been emerging as important for NES design and operation is flexibility. The need to reduce installation and operational costs, while facilitating maintenance is promoting a more rational use of the available resources at run-time, exploring the ability to tune service parameters as the system evolves. However, such operational flexibility comes with the cost of increasing the complexity of the system to handle the dynamic resource management, which on the other hand demands the allocation of additional system resources. Moreover, the capacity to dynamically modify the system properties also causes a higher complexity when designing and specifying the system, since the operational state-space increases with the degrees of flexibility of the system. Therefore, in order to bound this complexity appropriate operational models are needed to handle the system dynamics and carry on an efficient and fair resource management strategy based on quality of service (QoS) metrics. This thesis states that the properties of flexibility and timeliness as needed for dynamic QoS management can be provided to switched Ethernet based systems. Switched Ethernet, although initially designed for general purpose Internet access and file transfers, is becoming widely used in NES-based applications. However, COTS switched Ethernet is insufficient regarding the needs for real-time predictability and for supporting the aforementioned properties due the use of FIFO queues too few priority levels and for stream-level management capabilities. In this dissertation we propose a protocol to overcome those limitations, namely the Flexible Time-Triggered communication over Switched Ethernet (FTT-SE). The protocol is based on the FTT paradigm that generically defines a protocol architecture suitable to enforce real-time determinism on a communication network supporting the desired flexibility properties. This dissertation addresses the motivation for FTT-SE, describing the protocol as well as its schedulability analysis. It additionally covers the resource distribution topic, where several distribution models are proposed to manage the resource capacity among the competing services and while considering the QoS level requirements of each service. A couple of application cases are shown that support the aforementioned thesis

A stereoscopic video transmission algorithm for an IPTV network based on empirical data

IPTV service is one of the topics where industry and academia are providing more efforts with the purpose of enhancing the systems in existence. One of the potentially biggest advantages of IPTV is the existence of a return channel from the customer to the IPTV service provider, which makes this technology the upcoming TV distribution system. The next big step is to serve stereoscopic video over IP networks. In this paper, we evaluate the stereoscopic video transmission over IP by taking measurements of the bandwidth, delay and jitter. These measurements are useful to test the QoS and QoE of the ITPV service and to demonstrate the need for high-performance stereoscopic compression codecs. Then, we study the performance of four free codecs in order to propose an algorithm to perform the appropriate decisions to transmit stereoscopic video in the IPTV network properly. The algorithm is based on the empirical data obtained from our test and on some analytical considerations. Finally, we show the impact on the network given by the algorithm, and we compare the QoS parameters when each codec is chosen. © 2011 John Wiley & Sons, Ltd.Lloret, J.; García Pineda, M.; Canovas Solbes, A.; Turró Ribalta, C. (2011). A stereoscopic video transmission algorithm for an IPTV network based on empirical data. International Journal of Communication Systems. 24(10):1298-1329. doi:10.1002/dac.1196S129813292410IJsselsteijn W Seuntiëns P Meesters L ATTEST deliverable 1: state of the art in human factors and quality issues of stereoscopic broadcast television 2002Hawkins R Digital stereo video: display, compression and transmission 2002Campisi P Le Callet P Marini E Stereoscopic images quality assessmentBenoit, A., Le Callet, P., Campisi, P., & Cousseau, R. (2008). Quality Assessment of Stereoscopic Images. EURASIP Journal on Image and Video Processing, 2008, 1-13. doi:10.1155/2008/659024Coll BF Ishtiaq F O'Connell K 3DTV at home: status, challenges and solutions for delivering a high quality experienceMerkle P Brust H Dix K Wang Y Smolic A Adaptation and optimization of coding algorithms for mobile 3DTV 2008Zhou Y Hou C Jin Z Yang L Yang J Guo J 3DTV conference: the true vision-capture 1 4Tekalp, A., Kurutepe, E., & Civanlar, M. (2007). 3DTV over IP. IEEE Signal Processing Magazine, 24(6), 77-87. doi:10.1109/msp.2007.905878Vetro A Matusik W Pfister H Xin J Coding approaches for end-to-end 3D TV systemsAgrawal D Baldi M Corrà M Fontana G Marchetto G Nguyen VT Ofek Y Severina D Truong TH Zadedyurina O A scalable approach for supporting streaming media: design, implementation and experimentsPetrovic, G., Farin, D., & de With, P. H. N. (2008). Toward 3D-IPTV: design and implementation of a stereoscopic and multiple-perspective video streaming system. Stereoscopic Displays and Applications XIX. doi:10.1117/12.766327Kim J Choi K Lee H Kim JW Multi-view 3D video transport using application layer multicast with view switching delay constraints 1 4Fecker U Kaup A Transposed picture ordering for dynamic light field coding 2004David Hugh M 3D Video transmission 1993 http://www.freepatentsonline.com/EP0267000B1.htmlHewage CTER Worrall S Dogan S Kodikara Arachchi H Kondoz AM Stereoscopic TV over IP 1 7Woods A Docherty T Koch R Image distortions in stereoscopic video systems 1993Fehn C A 3D-TV approach using depth-image-based rendering (DIBR)Kurutepe, E., Civanlar, M. R., & Tekalp, A. M. (2007). Client-Driven Selective Streaming of Multiview Video for Interactive 3DTV. IEEE Transactions on Circuits and Systems for Video Technology, 17(11), 1558-1565. doi:10.1109/tcsvt.2007.903664Shimizu S Kimata H Ohtani Y Real-time free-viewpoint viewer from multiview video plus depth representation coded by H.264/AVC MVC estensionOh, K.-J., Kim, M., Yoon, J. S., Kim, J., Park, I., Lee, S., … Ho, Y.-S. (2007). Multi-View Video and Multi-Channel Audio Broadcasting System. 2007 3DTV Conference. doi:10.1109/3dtv.2007.4379437Koenen R Overview of the MPEG-4 standard 2002 http://mpeg.chiariglione.org/standards/mpeg-4/mpeg-4.htmHewage CTER Karim HA Worrall S Dogan S Kondoz AM Comparison of stereo video coding support in MPEG-4 MAC, H.264/AVC and H.264/SVCFiandrotti A Masala E De Martin JC Rate-distortion optimized H.264/MVC video communications over QoS-enabled NetworksBalaško H Comparison of compression algorithms for high definition and super high definition video signals http://www.fer.hr/_download/repository/KDI_Balasko_(1).pdfhttp://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_detail.htm?csnumber=39259http://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_detail.htm?csnumber=52974http://www.videolan.org/vlc/http://www.ray3d.com/free.htmlhttp://www.effectmatrix.com/total-video-converterAtenas M Cánovas A Garcia M Lloret J IPTV transcoding to avoid network congestion 36 41ITU-R Recommendation BT.500: Methodology for the subjective assessment of the quality of television pictures 2002 http://www.itu.int/rec/R-REC-BT/enhttp://www.matroska.org/technical/specs/codecid/index.htmlVASSILAKIS, V. G., MOSCHOLIOS, I. D., & LOGOTHETIS, M. D. (2008). Call-Level Performance Modelling of Elastic and Adaptive Service-Classes with Finite Population. IEICE Transactions on Communications, E91-B(1), 151-163. doi:10.1093/ietcom/e91-b.1.151Vassilakis VG Moscholios ID Logothetis MD Evaluation of multi-rate loss models for elastic trafficBouras, C., & Gkamas, A. (2003). Multimedia transmission with adaptive QoS based on real-time protocols. International Journal of Communication Systems, 16(3), 225-248. doi:10.1002/dac.58