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Multimedia delivery in the future internet
The term âNetworked Mediaâ implies that all kinds of media including text, image, 3D graphics, audio
and video are produced, distributed, shared, managed and consumed on-line through various networks,
like the Internet, Fiber, WiFi, WiMAX, GPRS, 3G and so on, in a convergent manner [1]. This white
paper is the contribution of the Media Delivery Platform (MDP) cluster and aims to cover the Networked
challenges of the Networked Media in the transition to the Future of the Internet.
Internet has evolved and changed the way we work and live. End users of the Internet have been confronted
with a bewildering range of media, services and applications and of technological innovations concerning
media formats, wireless networks, terminal types and capabilities. And there is little evidence that the pace
of this innovation is slowing. Today, over one billion of users access the Internet on regular basis, more
than 100 million users have downloaded at least one (multi)media file and over 47 millions of them do so
regularly, searching in more than 160 Exabytes1 of content. In the near future these numbers are expected
to exponentially rise. It is expected that the Internet content will be increased by at least a factor of 6, rising
to more than 990 Exabytes before 2012, fuelled mainly by the users themselves. Moreover, it is envisaged
that in a near- to mid-term future, the Internet will provide the means to share and distribute (new)
multimedia content and services with superior quality and striking flexibility, in a trusted and personalized
way, improving citizensâ quality of life, working conditions, edutainment and safety.
In this evolving environment, new transport protocols, new multimedia encoding schemes, cross-layer inthe
network adaptation, machine-to-machine communication (including RFIDs), rich 3D content as well as
community networks and the use of peer-to-peer (P2P) overlays are expected to generate new models of
interaction and cooperation, and be able to support enhanced perceived quality-of-experience (PQoE) and
innovative applications âon the moveâ, like virtual collaboration environments, personalised services/
media, virtual sport groups, on-line gaming, edutainment. In this context, the interaction with content
combined with interactive/multimedia search capabilities across distributed repositories, opportunistic P2P
networks and the dynamic adaptation to the characteristics of diverse mobile terminals are expected to
contribute towards such a vision.
Based on work that has taken place in a number of EC co-funded projects, in Framework Program 6 (FP6)
and Framework Program 7 (FP7), a group of experts and technology visionaries have voluntarily
contributed in this white paper aiming to describe the status, the state-of-the art, the challenges and the way
ahead in the area of Content Aware media delivery platforms
Network coding meets multimedia: a review
While every network node only relays messages in a traditional communication system, the recent network coding (NC) paradigm proposes to implement simple in-network processing with packet combinations in the nodes. NC extends the concept of "encoding" a message beyond source coding (for compression) and channel coding (for protection against errors and losses). It has been shown to increase network throughput compared to traditional networks implementation, to reduce delay and to provide robustness to transmission errors and network dynamics. These features are so appealing for multimedia applications that they have spurred a large research effort towards the development of multimedia-specific NC techniques. This paper reviews the recent work in NC for multimedia applications and focuses on the techniques that fill the gap between NC theory and practical applications. It outlines the benefits of NC and presents the open challenges in this area. The paper initially focuses on multimedia-specific aspects of network coding, in particular delay, in-network error control, and mediaspecific error control. These aspects permit to handle varying network conditions as well as client heterogeneity, which are critical to the design and deployment of multimedia systems. After introducing these general concepts, the paper reviews in detail two applications that lend themselves naturally to NC via the cooperation and broadcast models, namely peer-to-peer multimedia streaming and wireless networkin
Robust P2P Live Streaming
Projecte fet en col.laboraciĂł amb la FundaciĂł i2CATThe provisioning of robust real-time communication services (voice, video, etc.) or media contents through the Internet in a distributed manner is an important challenge,
which will strongly influence in current and future Internet evolution. Aware of this, we
are developing a project named Trilogy leaded by the i2CAT Foundation, which has as
main pillar the study, development and evaluation of Peer-to-Peer (P2P) Live
streaming architectures for the distribution of high-quality media contents. In this
context, this work concretely covers media coding aspects and proposes the use of
Multiple Description Coding (MDC) as a flexible solution for providing robust and
scalable live streaming over P2P networks. This work describes current state of the art
in media coding techniques and P2P streaming architectures, presents the
implemented prototype as well as its simulation and validation results
Detection of encrypted traffic generated by peer-to-peer live streaming applications using deep packet inspection
The number of applications using the peer-to-peer (P2P) networking paradigm and their popularity has substantially grown over the last decade. They evolved from the le-sharing applications to media streaming ones. Nowadays these applications commonly encrypt the communication contents or employ protocol obfuscation techniques. In this dissertation, it was conducted an investigation to identify encrypted traf c ows generated by three of the most popular P2P live streaming applications: TVUPlayer, Livestation and GoalBit. For this work, a test-bed that could simulate a near real scenario was created, and traf c was captured from a great variety of applications. The method proposed resort to Deep Packet Inspection (DPI), so we needed
to analyse the payload of the packets in order to nd repeated patterns, that later were used to create a set of SNORT rules that can be used to detect key network packets generated by these applications. The method was evaluated experimentally on the test-bed created for that purpose, being shown that its accuracy is of 97% for GoalBit.A popularidade e o nĂșmero de aplicaçÔes que usam o paradigma de redes par-a-par (P2P)
tĂȘm crescido substancialmente na Ășltima dĂ©cada. Estas aplicaçÔes deixaram de serem usadas
simplesmente para partilha de ficheiros e sĂŁo agora usadas tambĂ©m para distribuir conteĂșdo
multimĂ©dia. Hoje em dia, estas aplicaçÔes tĂȘm meios de cifrar o conteĂșdo da comunicação
ou empregar técnicas de ofuscação directamente no protocolo. Nesta dissertação, foi realizada
uma investigação para identificar fluxos de tråfego encriptados, que foram gerados por
trĂȘs aplicaçÔes populares de distribuição de conteĂșdo multimĂ©dia em redes P2P: TVUPlayer,
Livestation e GoalBit. Para este trabalho, foi criada uma plataforma de testes que pretendia
simular um cenĂĄrio quase real, e o trĂĄfego que foi capturado, continha uma grande variedade
de aplicaçÔes. O método proposto nesta dissertação recorre à técnica de Inspecção Profunda
de Pacotes (DPI), e por isso, foi necessĂĄrio 21nalisar o conteĂșdo dos pacotes a fim de encontrar
padrÔes que se repetissem, e que iriam mais tarde ser usados para criar um conjunto de regras
SNORT para detecção de pacotes chave· na rede, gerados por estas aplicaçÔes, afim de se
poder correctamente classificar os fluxos de tråfego. Após descobrir que a aplicação Livestation
deixou de funcionar com P2P, apenas as duas regras criadas até esse momento foram usadas.
Quanto à aplicação TVUPlayer, foram criadas vårias regras a partir do tråfego gerado por ela
mesma e que tiveram uma boa taxa de precisão. Vårias regras foram também criadas para
a aplicação GoalBit em que foram usados quatro cenårios: com e sem encriptação usando a
opção de transmissão tracker, e com e sem encriptação usando a opção de transmissão sem
necessidade de tracker (aqui foi usado o protocolo Kademlia). O método foi avaliado experimentalmente
na plataforma de testes criada para o efeito, sendo demonstrado que a precisĂŁo
do conjunto de regras para a aplicação GoallBit Ă© de 97%.Fundação para a CiĂȘncia e a Tecnologia (FCT
Multiple description image and video coding for P2P transmissions
Peer-to-Peer (P2P) media streaming is, nowadays, a very attractive topic due to the bandwidth available to serve demanding content scales. A key challenge, however, is making content distribution robust to peer transience. Multiple description coding (MDC) has, indeed, proven to be very effective with problems concerning the packetsâ losses, since it generates several descriptions and may reconstruct the original information with any number of descriptions that may reach the decoder. Therefore multiple descriptions may be effective for robust peer-to-peer media streaming. In this dissertation, it will not only be showed that, but also that varying the redundancy level of description on the fly may lead to a better performance than the one obtained without varying this parameter. Besides that, it is shown, as well, that varying the Bitrate on the fly outperforms the redundancy on it. Furthermore, the redundancy and the Bitrate were varied simultaneously. Thus, it is shown that this variation is more efficient when the packet loss is high.
The experiments reported above were done using an experimental test bed developed for this purpose at the NMCG lab of the University of Beira Interior. It was also used the REGPROT, a video encoder developed by our research team, to splitted the video into multiple descriptions, which were, later, distributed among the peers in the test bed. After the request of the client, the referred encoder decoded the descriptions as they were being received.Fundação para a CiĂȘncia e a Tecnologia (FCT
Diseño centrado en calidad para la difusión Peer-to-Peer de video en vivo
El uso de redes Peer-to-Peer (P2P) es una forma escalable para ofrecer servicios de video sobre Internet. Este documento hace foco en la definiciĂłn, desarrollo y evaluaciĂłn de una arquitectura P2P para distribuir video en vivo. El diseño global de la red es guiado por la calidad de experiencia (Quality of Experience - QoE), cuyo principal componente en este caso es la calidad del video percibida por los usuarios finales, en lugar del tradicional diseño basado en la calidad de servicio (Quality of Service - QoE) de la mayorĂa de los sistemas. Para medir la calidad percibida del video, en tiempo real y automĂĄticamente, extendimos la recientemente propuesta metodologĂa Pseudo-Subjective Quality Assessment (PSQA). Dos grandes lĂneas de investigaciĂłn son desarrolladas. Primero, proponemos una tĂ©cnica de distribuciĂłn de video desde mĂșltiples fuentes con las caracterĂsticas de poder ser optimizada para maximizar la calidad percibida en contextos de muchas fallas y de poseer muy baja señalizaciĂłn (a diferencia de los sistemas existentes). Desarrollamos una metodologĂa, basada en PSQA, que nos permite un control fino sobre la forma en que la señal de video es dividida en partes y la cantidad de redundancia agregada, como una funciĂłn de la dinĂĄmica de los usuarios de la red. De esta forma es posible mejorar la robustez del sistema tanto como sea deseado, contemplando el lĂmite de capacidad en la comunicaciĂłn. En segundo lugar, presentamos un mecanismo estructurado para controlar la topologĂa de la red. La selecciĂłn de que usuarios servirĂĄn a que otros es importante para la robustez de la red, especialmente cuando los usuarios son heterogĂ©neos en sus capacidades y en sus tiempos de conexiĂłn.Nuestro diseño maximiza la calidad global esperada (evaluada usando PSQA), seleccionado una topologĂa que mejora la robustez del sistema. AdemĂĄs estudiamos como extender la red con dos servicios complementarios: el video bajo demanda (Video on Demand - VoD) y el servicio MyTV. El desafĂo en estos servicios es como realizar bĂșsquedas eficientes sobre la librerĂa de videos, dado al alto dinamismo del contenido. Presentamos una estrategia de "caching" para las bĂșsquedas en estos servicios, que maximiza el nĂșmero total de respuestas correctas a las consultas, considerando una dinĂĄmica particular en los contenidos y restricciones de ancho de banda. Nuestro diseño global considera escenarios reales, donde los casos de prueba y los parĂĄmetros de configuraciĂłn surgen de datos reales de un servicio de referencia en producciĂłn. Nuestro prototipo es completamente funcional, de uso gratuito, y basado en tecnologĂas bien probadas de cĂłdigo abierto
A credit-based approach to scalable video transmission over a peer-to-peer social network
PhDThe objective of the research work presented in this thesis is to study
scalable video transmission over peer-to-peer networks. In particular,
we analyse how a credit-based approach and exploitation of social networking
features can play a significant role in the design of such systems.
Peer-to-peer systems are nowadays a valid alternative to the traditional
client-server architecture for the distribution of multimedia content, as
they transfer the workload from the service provider to the final user,
with a subsequent reduction of management costs for the former. On
the other hand, scalable video coding helps in dealing with network
heterogeneity, since the content can be tailored to the characteristics
or resources of the peers. First of all, we present a study that evaluates
subjective video quality perceived by the final user under different
transmission scenarios. We also propose a video chunk selection algorithm
that maximises received video quality under different network
conditions. Furthermore, challenges in building reliable peer-to-peer
systems for multimedia streaming include optimisation of resource allocation
and design mechanisms based on rewards and punishments that
provide incentives for users to share their own resources. Our solution
relies on a credit-based architecture, where peers do not interact with
users that have proven to be malicious in the past. Finally, if peers
are allowed to build a social network of trusted users, they can share
the local information they have about the network and have a more
complete understanding of the type of users they are interacting with.
Therefore, in addition to a local credit, a social credit or social reputation
is introduced. This thesis concludes with an overview of future
developments of this research work
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