35 research outputs found
An autonomic delivery framework for HTTP adaptive streaming in multicast-enabled multimedia access networks
The consumption of multimedia services over HTTP-based delivery mechanisms has recently gained popularity due to their increased flexibility and reliability. Traditional broadcast TV channels are now offered over the Internet, in order to support Live TV for a broad range of consumer devices. Moreover, service providers can greatly benefit from offering external live content (e. g., YouTube, Hulu) in a managed way. Recently, HTTP Adaptive Streaming (HAS) techniques have been proposed in which video clients dynamically adapt their requested video quality level based on the current network and device state. Unlike linear TV, traditional HTTP- and HAS-based video streaming services depend on unicast sessions, leading to a network traffic load proportional to the number of multimedia consumers. In this paper we propose a novel HAS-based video delivery architecture, which features intelligent multicasting and caching in order to decrease the required bandwidth considerably in a Live TV scenario. Furthermore we discuss the autonomic selection of multicasted content to support Video on Demand (VoD) sessions. Experiments were conducted on a large scale and realistic emulation environment and compared with a traditional HAS-based media delivery setup using only unicast connections
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
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
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
Adaptation and Robustness in Peer-to-Peer Streaming
The rapid development of network communication infrastructure enables networked multimedia streaming applications ranging from on-demand video streaming to highly interactive video conferencing. Peer-to-Peer (P2P) technologies have emerged as a powerful and popular paradigm for bringing such emerging multimedia services to a large number of users. The essential advantage of P2P systems is that the system capacity scales up when more peers join, as peer upload capacity is utilized. However, providing satisfactory streaming services over P2P networks is challenging because of their inherent instability and unreliability and the limited adaptability of traditional video coding techniques. On one hand, different from dedicated servers, users may not have enough bandwidth to serve other users as most user connections are asymmetric in their upload and download capacity, and they are heterogeneous in terms of bandwidth and preferences. In addition, users can join and leave the system at any time as there are no guarantees on their contribution to the system. On the other hand, although traditional video coding techniques are efficient in terms of resource consumption, compression ratio, and coding and decoding speed, they do not support scalable modes efficiently as such modes come along with high computation cost. Consequently, in traditional P2P streaming systems, the bit rate (the video quality) of media streams is determined based on the capacities of the low-end users, i.e. the lowest common denominator, to make sure that most of their users can perceive acceptable quality. This causes two critical limitations of the current P2P streaming systems. First, users perceive the same quality regardless of their bandwidth capacity, i.e., no differentiated QoS. Second, with the current best-effort Internet and peer dynamics, the streaming quality at each peer is easily impaired, i.e., no continuous playback.
Recently, multiple layer codec research has become more refined, as SVC (the scalable extension of the H.264/AVC standard) has been standardized with a bit rate overhead of around 10% and an indistinguishable visual quality compared to the state of the art single layer codec. The hypothesis of this research work is that the adaptable coding technique can bring significant benefits to P2P streaming as it enables adaptability in P2P streaming. In addition, to improve the robustness of the system to network fluctuations and peer dynamics, network coding and social networking are also applied. The overall goal of this research is to achieve adaptive and robust P2P streaming services, which are believed to be the next generation of P2P streaming on the Internet. Several major contributions are presented in this dissertation. First, to use SVC in P2P streaming, a segmentation method to segment SVC streams into scalable units is proposed such that they can be delivered adaptively by the P2P paradigm. The method is demonstrated to be able to preserve the scalability features of a stream, i.e., adaptation can be applied on segments and the re-generated stream at each peer is a valid stream. Second, a novel and complete adaptive P2P streaming protocol, named Chameleon, is presented. Chameleon uses the segmentation method to use SVC and combine it with network coding in P2P streaming to achieve high performance streaming. The core of Chameleon is studied, including neighbor selection, quality adaptation, receiver-driven peer coordination, and sender selection, with different design options. Experiments on Chameleon reveal that overlay construction is important to system performance, and traditional gossip-based protocols are not good enough for layered P2P streaming. Therefore, third, a SCAMP-based neighbor selection protocol and a peer sampling-based membership management protocol for layered P2P streaming are proposed. These gossip-based protocols are quality- and context-aware as they form robust and adaptable overlays for layered P2P streaming so that high capacity peers have a higher priority to be located at good positions in the overlay, e.g. closer to the server, and peers with similar capacity are connected to each other to better utilize resources. Fourth, to better deal with peer dynamics, Stir, a social-based P2P streaming system, is suggested. In Stir, the novel idea of spontaneous social networking is introduced. Stir users who join the same streaming session can make friends and communicate with each other by cheap yet efficient communication means, e.g., instant messaging and Twitter-like commenting. Such friendship networks are exploited directly by the underlying social-based P2P streaming protocol. The tight integration between the high level social networking of users and the low level overlay of peers is demonstrated to be beneficial in dealing with high churn rates and providing personalized streaming services. Finally, as the approaches are about different aspects of adaptive and robust P2P streaming, to complete the picture, Chameleon++, which combines Chameleon and Stir, is presented. The design and the evaluation of Chameleon++ demonstrate the feasibility and the benefits of the approaches, and the consistency of the study
Video-on-Demand over Internet: a survey of existing systems and solutions
Video-on-Demand is a service where movies are delivered to distributed users with low delay and free interactivity. The traditional client/server architecture experiences scalability issues to provide video streaming services, so there have been many proposals of systems, mostly based on a peer-to-peer or on a hybrid server/peer-to-peer solution, to solve this issue. This work presents a survey of the currently existing or proposed systems and solutions, based upon a subset of representative systems, and defines selection criteria allowing to classify these systems. These criteria are based on common questions such as, for example, is it video-on-demand or live streaming, is the architecture based on content delivery network, peer-to-peer or both, is the delivery overlay tree-based or mesh-based, is the system push-based or pull-based, single-stream or multi-streams, does it use data coding, and how do the clients choose their peers. Representative systems are briefly described to give a summarized overview of the proposed solutions, and four ones are analyzed in details. Finally, it is attempted to evaluate the most promising solutions for future experiments. RĂ©sumĂ© La vidĂ©o Ă la demande est un service oĂč des films sont fournis Ă distance aux utilisateurs avec u
Scalable Video Streaming with Prioritised Network Coding on End-System Overlays
PhDDistribution over the internet is destined to become a standard approach for live broadcasting
of TV or events of nation-wide interest. The demand for high-quality live video
with personal requirements is destined to grow exponentially over the next few years. Endsystem
multicast is a desirable option for relieving the content server from bandwidth bottlenecks
and computational load by allowing decentralised allocation of resources to the users
and distributed service management. Network coding provides innovative solutions for a
multitude of issues related to multi-user content distribution, such as the coupon-collection
problem, allocation and scheduling procedure. This thesis tackles the problem of streaming
scalable video on end-system multicast overlays with prioritised push-based streaming.
We analyse the characteristic arising from a random coding process as a linear channel
operator, and present a novel error detection and correction system for error-resilient decoding,
providing one of the first practical frameworks for Joint Source-Channel-Network
coding. Our system outperforms both network error correction and traditional FEC coding
when performed separately. We then present a content distribution system based on endsystem
multicast. Our data exchange protocol makes use of network coding as a way to
collaboratively deliver data to several peers. Prioritised streaming is performed by means
of hierarchical network coding and a dynamic chunk selection for optimised rate allocation
based on goodput statistics at application layer. We prove, by simulated experiments, the
efficient allocation of resources for adaptive video delivery. Finally we describe the implementation
of our coding system. We highlighting the use rateless coding properties, discuss
the application in collaborative and distributed coding systems, and provide an optimised
implementation of the decoding algorithm with advanced CPU instructions. We analyse
computational load and packet loss protection via lab tests and simulations, complementing
the overall analysis of the video streaming system in all its components
Flexible media transport framework based on service composition for future network
This work introduces common guidelines defined in several standardization organisms towards future networks based on the actual mechanisms and protocols used to treat the
multimedia data, most of them placed in the application layer of the OSI reference model.Peer ReviewedPreprin
Joint coding/decoding techniques and diversity techniques for video and HTML transmission over wireless point/multipoint: a survey
I. Introduction
The concomitant developments of the Internet, which offers to its users always larger and more evolved contents (from
HTML (HyperText Markup Language) files to multimedia applications), and of wireless systems and handhelds integrating
them, have progressively convinced a fair share of people of the interest to always be connected. Still, constraints of
heterogeneity, reliability, quality and delay over the transmission channels are generally imposed to fulfill the
requirements of these new needs and their corresponding economical goals. This implies different theoretical and
practical challenges for the digital communications community of the present time.
This paper presents a survey of the different techniques existing in the domain of HTML and video stream transmission
over erroneous or lossy channels. In particular, the existing techniques on joint source and channel coding and decoding
for multimedia or HTML applications are surveyed, as well as the related problems of streaming and downloading files
over an IP mobile link. Finally, various diversity techniques that can be considered for such links, from antenna diversity
to coding diversity, are presented...Lâengouement du grand public pour les applications multimĂ©dia sans fil ne cesse de croĂźtre depuis
le dĂ©veloppement dâInternet. Des contraintes dâhĂ©tĂ©rogĂ©nĂ©itĂ© de canaux de transmission, de fiabilitĂ©,
de qualité et de délai sont généralement exigées pour satisfaire les nouveaux besoins applicatifs entraßnant
ainsi des enjeux Ă©conomiques importants. Ă lâheure actuelle, il reste encore un certain nombre de dĂ©fis
pratiques et thĂ©oriques lancĂ©s par les chercheurs de la communautĂ© des communications numĂ©riques. Câest
dans ce cadre que sâinscrit le panorama prĂ©sentĂ© ici.
Cet article prĂ©sente dâune part un Ă©tat de lâart sur les principales techniques de codage et de dĂ©codage
conjoint développées dans la littérature pour des applications multimédia de type téléchargement et diffusion
de contenu sur lien mobile IP. Sont tout dâabord rappelĂ©es des notions fondamentales des communications
numériques à savoir le codage de source, le codage de canal ainsi que les théorÚmes de Shannon et leurs
principales limitations. Les techniques de codage décodage conjoint présentées dans cet article concernent
essentiellement celles développées pour des schémas de codage de source faisant intervenir des codes
Ă longueur variable (CLV) notamment les codes dâHuffman, arithmĂ©tiques et les codes entropiques universels
de type Lempel-Ziv (LZ). Faisant face au problÚme de la transmission de données (Hypertext Markup
Language (HTML) et vidĂ©o) sur un lien sans fil, cet article prĂ©sente dâautre part un panorama de techniques de diversitĂ©s plus ou moins complexes en vue dâintroduire le nouveau
systĂšme Ă multiples antennes dâĂ©mission et de rĂ©ception