The Experts below are selected from a list of 39081 Experts worldwide ranked by ideXlab platform
Thomas Wiegand - One of the best experts on this subject based on the ideXlab platform.
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Packet Level video quality evaluation of extensive H.264/AVC and SVC transmission simulation
Journal of Internet Services and Applications, 2011Co-Authors: Robert Skupin, Cornelius Hellge, Thomas Schierl, Thomas WiegandAbstract:Video transmission over error prone channels as present in most of today’s communication channels, such as Mobile TV or some IPTV systems, is constantly subject to research. Simulation is an important instrument to evaluate performance of the overall video transmission system, but the multitude of parameters often requires large and time-consuming simulation sets. In this paper, we present a Packet Level mechanism for fast evaluation of error-prone H.264/AVC and SVC video transmission with application layer video quality metrics, such as PSNR. Our approach significantly reduces the overall simulation time by eliminating redundancy in the evaluation phase and utilizing the prediction structure of the video codec. The benefit of the presented Packet Level video quality evaluation is evaluated with an exemplary simulation setup of an IPTV service with link congestion.
Ivan V. Bajic - One of the best experts on this subject based on the ideXlab platform.
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DMS - Modeling and analysis of multipath video transport over lossy networks using Packet-Level FEC
2005Co-Authors: James W. Modestino, Ivan V. BajicAbstract:The use of forward error correction (FEC) coding is often proposed to combat the effects of network Packet losses for error-resilient video transmission on Packet-switched networks. On the other hand, path diversity has recently been proposed to improve network transport for both singledescription (SD) and multiple-description (MD) coded video. In this work we model and analyze an SD coded video transmission system employing Packet-Level FEC in combination with path diversity. In particular, we provide a precise analytical approach to evaluating the efficacy of path diversity in reducing the burstiness of network Packet-loss processes. We use this approach to quantitatively demonstrate the advantages of path diversity in improving end-to-end video transport performance using Packet-Level FEC.
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ICIP (2) - Performance analysis of the efficacy of Packet-Level FEC in improving video transport over networks
IEEE International Conference on Image Processing 2005, 2005Co-Authors: James W. Modestino, Ivan V. BajicAbstract:Packet video transport over networks is expected to experience Packet losses due to congestion, link failures and timeouts. Packet-Level FEC is often proposed to combat these Packet losses and thus improve received video quality. However, the redundant Packets associated with the FEC coding will increase the effective network load and, as a result, further exacerbate the network Packet-loss rates. In this work, we propose a model framework to describe FEC-protected Packet video network transport systems and analytically investigate the overall efficacy of Packet-Level FEC in improving the end-to-end video quality. We consider a simplified network scenario, where the network congestion performance can be described in terms of a single bottleneck node, modeled as a multiplexer. Our results show that Packet-Level FEC can significantly improve the end-to-end video quality provided that the coding block size is large enough and the coding rate is appropriately chosen, assuming other system parameters are likewise appropriately chosen. We also demonstrate that, when multiple sources share the multiplexer, FEC coding can achieve significant multiplexing gain in terms of the number of video sources that can be supported for a given end-to-end performance.
Roch Guerin - One of the best experts on this subject based on the ideXlab platform.
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Packet Level diversity from theory to practice an 802 11 based experimental investigation
ACM IEEE International Conference on Mobile Computing and Networking, 2006Co-Authors: Evangelos Vergetis, Eric A. Pierce, Marc Blanco, Roch GuerinAbstract:Packet-Level diversity, or distributing Packet transmissions over multiple, diverse channels, offers benefits in improving communication performance and robustness to channel variations. Previous works have analyzed and quantified those benefits, and developed transmission policies to realize them. However, translating those benefits into practice still faces numerous challenges from uncertainty in the adequacy of the channel models used to develop policies, to implementation dificulties in realizing the precise transmission schedules they mandate. This work is a first step in assessing what remains of those benefits once confronted with such practical challenges. Our investigation is carried out over an 802.11 testbed, where diversity is realized through the different frequency bands available for transmissions between hosts and access points. We use the testbed to evaluate the impact of transmission policies, channel characteristics, channel correlation, and various end-system constraints that affect our ability to precisely control transmissions timing. Our investigation reveals that in spite of the many gaps that exist between theory and practice, Packet-Level diversity still provides a simple solution to improve transmission performance and robustness across a broad range of configurations.
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MobiCom - Packet-Level diversity - from theory to practice: an 802.11-based experimental investigation
Proceedings of the 12th annual international conference on Mobile computing and networking - MobiCom '06, 2006Co-Authors: Evangelos Vergetis, Eric A. Pierce, Marc Blanco, Roch GuerinAbstract:Packet-Level diversity, or distributing Packet transmissions over multiple, diverse channels, offers benefits in improving communication performance and robustness to channel variations. Previous works have analyzed and quantified those benefits, and developed transmission policies to realize them. However, translating those benefits into practice still faces numerous challenges from uncertainty in the adequacy of the channel models used to develop policies, to implementation dificulties in realizing the precise transmission schedules they mandate. This work is a first step in assessing what remains of those benefits once confronted with such practical challenges. Our investigation is carried out over an 802.11 testbed, where diversity is realized through the different frequency bands available for transmissions between hosts and access points. We use the testbed to evaluate the impact of transmission policies, channel characteristics, channel correlation, and various end-system constraints that affect our ability to precisely control transmissions timing. Our investigation reveals that in spite of the many gaps that exist between theory and practice, Packet-Level diversity still provides a simple solution to improve transmission performance and robustness across a broad range of configurations.
Alberto Dainotti - One of the best experts on this subject based on the ideXlab platform.
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classification of network traffic via Packet Level hidden markov models
Global Communications Conference, 2008Co-Authors: Alberto Dainotti, Antonio Pescape, W De Donato, Salvo P RossiAbstract:Traffic classification and identification is a fertile research area. Beyond Quality of Service, service differentiation, and billing, one of the most important applications of traffic classification is in the field of network security. This paper proposes a Packet-Level traffic classification approach based on Hidden Markov Model (HMM). Classification is performed by using real network traffic and estimating - in a combined fashion - Packet Size (PS) and Inter Packet Time (IPT) characteristics, thus remaining applicable to encrypted traffic too. The effectiveness of the proposed approach is evaluated by considering several traffic typologies: we applied our model to real traffic traces of Age of Mythology and Counter Strike (two Multi Player Network Games), HTTP, SMTP, Edonkey, PPlive (a peer-to-peer IPTV application), and MSN Messenger. An analytical basis and the mathematical details regarding the model are given. Results show how the proposed approach is able to classify network traffic by using Packet-Level statistical properties and therefore it is a good candidate as a component for a multi-classification framework.
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GLOBECOM - Classification of Network Traffic via Packet-Level Hidden Markov Models
IEEE GLOBECOM 2008 - 2008 IEEE Global Telecommunications Conference, 2008Co-Authors: Alberto Dainotti, Antonio Pescape, W De Donato, P. Salvo RossiAbstract:Traffic classification and identification is a fertile research area. Beyond Quality of Service, service differentiation, and billing, one of the most important applications of traffic classification is in the field of network security. This paper proposes a Packet-Level traffic classification approach based on Hidden Markov Model (HMM). Classification is performed by using real network traffic and estimating - in a combined fashion - Packet Size (PS) and Inter Packet Time (IPT) characteristics, thus remaining applicable to encrypted traffic too. The effectiveness of the proposed approach is evaluated by considering several traffic typologies: we applied our model to real traffic traces of Age of Mythology and Counter Strike (two Multi Player Network Games), HTTP, SMTP, Edonkey, PPlive (a peer-to-peer IPTV application), and MSN Messenger. An analytical basis and the mathematical details regarding the model are given. Results show how the proposed approach is able to classify network traffic by using Packet-Level statistical properties and therefore it is a good candidate as a component for a multi-classification framework.
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a Packet Level traffic model of starcraft
Second International Workshop on Hot Topics in Peer-to-Peer Systems, 2005Co-Authors: Alberto Dainotti, Antonio Pescape, G VentreAbstract:Starcraft is a popular real time strategy game that uses a peer-to-peer network communication model. In this paper we analyze its traffic and we provide a statistical characterization at Packet-Level obtained by varying the number of players. We examine the time dynamics between individual Packets within a game session as well as the Packet sizes. Also, we provide analytical models approximating the empirical distributions found, we study properties of the tails and of the auto-correlation function, and we investigate the presence of self-similarity. The results obtained show how traffic generated by such game has different characteristics from the traffic prevailing on the Internet in past years.
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CAMAD - A Packet-Level characterization of network traffic
2006 11th Intenational Workshop on Computer-Aided Modeling Analysis and Design of Communication Links and Networks, 1Co-Authors: Alberto Dainotti, Antonio Pescape, Giorgio VentreAbstract:In this paper we show results from a Packet-Level traffic characterization aiming at finding spatial and temporal invariances of TCP based applications, such as HTTP and SMTP. We developed a methodology and a software architecture to build Packet-Level statistical characterization of network traffic based on large traces captured from wide area networks. In order to show the efficacy of the proposed Packet-Level approach, we applied our methodology to the traffic generated by applications running over HTTP - a typology of traffic that has been extensively studied in literature even if, as far as we know, no accurate Packet-Level characterization has been proposed as yet with regard to it - and to SMTP traffic. We analyzed traffic from high-speed access links of two different networks and, contrary to common beliefs, the results show properties of spatial and temporal invariance. The study of SMTP has been proposed to demonstrate the generalization of a Packet-Level approach. Indeed, results prove the general applicability of the methodology and, at the same time, how - also at Packet Level - different traffic shows different characterizations. Characterization results can be used in platforms for traffic simulation (like ns or ssfnet) and traffic generation (like D-ITG or MGEM).
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HOT-P2P - A Packet-Level traffic model of Starcraft
Second International Workshop on Hot Topics in Peer-to-Peer Systems, 1Co-Authors: Alberto Dainotti, Antonio Pescape, Giorgio VentreAbstract:Starcraft is a popular real time strategy game that uses a peer-to-peer network communication model. In this paper we analyze its traffic and we provide a statistical characterization at Packet-Level obtained by varying the number of players. We examine the time dynamics between individual Packets within a game session as well as the Packet sizes. Also, we provide analytical models approximating the empirical distributions found, we study properties of the tails and of the auto-correlation function, and we investigate the presence of self-similarity. The results obtained show how traffic generated by such game has different characteristics from the traffic prevailing on the Internet in past years.
Roberta Fracchia - One of the best experts on this subject based on the ideXlab platform.
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VTC Spring - Analysis of Packet-Level Forward Error Correction for Video Transmission
2011 IEEE 73rd Vehicular Technology Conference (VTC Spring), 2011Co-Authors: Matteo Mazzotti, Enrico Paolini, Marco Chiani, Benjamin Gadat, Cyril Bergeron, Roberta FracchiaAbstract:In this paper, Packet-Level coding is considered in the framework of H.264/AVC video transmission. Two distinct solutions are proposed and compared in different realistic communication scenarios. The first is based on classical Reed-Solomon (RS) codes applied at the RTP layer, while the second on modern LDPC codes implemented at the UDP-Lite layer. An end-to-end Quality of Experience (QoE) evaluation is presented, in terms of achieved peak signal-to-noise power ratio (PSNR). Our numerical results show that, in low-latency video applications across communication channels introducing errors and erasures, the adoption of a Packet-Level coding scheme becomes essential to guarantee a satisfactory quality. The solution based on LDPC codes exhibits better performances in presence of severe Packet loss rates.
