On the use of adaptive media playout for inter-destination synchronization

[EN] Inter-Destination Multimedia Synchronization (IDMS) is essential in most of the emerging social multimedia applications. In this paper we present a novel Adaptive Media Playout (AMP) scheme that aims to acquire an overall synchronization status between distributed receivers by means of smoothly adjusting their playout timing. Simulation results show that the proposed solution minimizes long-term playout discontinuities (skips and/or pauses) which are subjectively more annoying to users than small variations in the media playout rate.This work was supported by the Universitat Politecnica de Valencia (UPV), under its R&D Support Program in the PAID-01-10 Project, and by Generalitat Valenciana, under its R&D Support Program in the GV 2010/009 Project.Montagud, M.; Boronat, F. (2011). On the use of adaptive media playout for inter-destination synchronization. IEEE Communications Letters. 15(9):863-865. https://doi.org/10.1109/LCOMM.2011.061611.110072S86386515

Design and assessment of a scalable and customizable low-cost tiled display system

© 2021 IEEE. Personal use of this material is permitted. Permissíon from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertisíng or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.[EN] In this paper, a scalable hardware and software architecture for low-cost tiled display systems (a.k.a. videowalls), customizable through a dynamic web-based management and configuration service is presented and evaluated both objectively and subjectively. It has been designed for both stored and live broadcast/broadband content, in mosaic or warp distributions. The videowalls can be dynamically configured via web in different ways: the displays can create a single screen of a larger size, or they can be configured in a customized way in order to playout different media contents in different display combinations. As display renderers, low-cost devices are proposed as the main hardware element to obtain affordable videowall systems. As a proof of concept, two prototypes have been implemented, including an accurate synchronization mechanism. To evidence the good performance of the prototypes and configuration service, Both objective and subjective evaluations have been conducted regarding synchronization accuracy and usability of the configuration service, obtaining satisfactory results.This work has been funded by the Generalitat Valenciana, through the R&D Program "Grants for research groups to be consolidated, AICO/2017" under Project AICO/2017/059.Marfil, D.; Boronat, F.; González-Salinas, J.; Vidal Meló, A. (2021). Design and assessment of a scalable and customizable low-cost tiled display system. IEEE Latin America Transactions. 19(5):708-716. https://doi.org/10.1109/TLA.2021.9448284S70871619

How to Perform AMP? Cubic Adjustments for Improving the QoE

[EN] Adaptive Media Playout (AMP) consists of smoothly and dynamically adjusting the media playout rate to recover from undesired (e.g., buffer overflow/underflow or out-of-sync) situations. The existing AMP solutions are mainly characterized by two main aspects. The first one is their goal (e.g., keeping the buffers¿ occupancy into safe ranges or enabling media synchronization). The second one is the criteria that determine the need for triggering the playout adjustments (e.g., buffer fullness or asynchrony levels). This paper instead focuses on a third key aspect, which has not been sufficiently investigated yet: the specific adjustment strategy to be performed. In particular, we propose a novel AMP strategy, called Cubic AMP, which is based on employing a cubic interpolation method to adjust a deviated playout point to a given reference. On the one hand, mathematical analysis and graphical examples show that our proposal provides superior performance than other existing linear and quadratic AMP strategies in terms of the smoothness of the playout curve, while significantly outperforming the quadratic AMP strategy regarding the duration of the adjustment period and without increasing the computational complexity. It has also been proved and discussed that higher-order polynomial interpolation methods are less convenient than cubic ones. On the other hand, the results of subjective tests confirm that our proposal provides better Quality of Experience (QoE) than the other existing AMP strategies.This work has been funded, partially, by the “Fondo Europeo de Desarrollo Regional (FEDER)” and the Spanish Ministry of Economy and Competitiveness, under its R&D&I Support Program, in project with Ref. TEC2013-45492-R.Montagud, M.; Boronat, F.; Roig, B.; Sapena Piera, A. (2017). How to Perform AMP? Cubic Adjustments for Improving the QoE. Computer Communications. 103:61-73. https://doi.org/10.1016/j.comcom.2017.01.017S617310

Implementation and Evaluation of an M/S Scheme for Inter-Destination Multimedia Synchronization (IDMS)

[EN] Nowadays, the media consumption model is changing from passive isolated activities towards dynamic group shared experiences. People separated in space can already interact and collaborate within the context of simultaneous media content delivery (e.g. they can launch a real time conversation during a shared video watching). However, to stimulate the acceptance and usability of those socially aware interactive media services, synchronous communications (i.e. consistent playout states) across separated locations must be guaranteed. Inter-Destination Multimedia Synchronization (IDMS) has become a key research topic to enable geographically dispersed consumers to experience a satisfying feeling of togetherness. Several (distributed and centralized) approaches to perform IDMS have been adopted by the research community up to date. In this paper, a Master/Slave (M/S) Control Scheme for IDMS is implemented and tested, thus analyzing its strengths and weaknesses for distributed networked environments. Simulation results prove the effectiveness and suitability of the proposed M/S Scheme in those scenarios in which scalability, consistency, interactivity and low control traffic overhead features must be provided.This work has been financed, partially, by Universitat Politècnica de Valencia (UPV), under its R&D Support Program in PAID-05-11-002-331 Project and in PAID-01-10.Montagud, M.; Boronat Segui, F. (2011). Implementation and Evaluation of an M/S Scheme for Inter-Destination Multimedia Synchronization (IDMS). Network Protocols and Algorithms. 3(3):80-98. https://doi.org/10.5296/npa.v3i3.1089S80983

Design, Development and Assessment of Control Schemes for IDMS in a Standardized RTCP-based Solution

[EN] Currently, several media sharing applications that allow social interactions between distributed users are gaining momentum. In these networked scenarios, synchronized playout between the involved participants must be provided to enable truly interactive and coherent shared media experiences. This research topic is known as Inter-Destination Media Synchronization (IDMS). This paper presents the design and development of an advanced IDMS solution, which is based on extending the capabilities of RTP/RTCP standard protocols. Particularly, novel RTCP extensions, in combination with several control algorithms and adjustment techniques, have been specified to enable an adaptive, highly accurate and standard compliant IDMS solution. Moreover, as different control or architectural schemes for IDMS exist, and each one is best suited for specific use cases, the IDMS solution has been extended to be able to adopt each one of them. Simulation results prove the satisfactory responsiveness of our IDMS solution in a small scale scenario, as well as its consistent behavior, when using each one of the deployed architectural schemes.This work has been financed, partially, by Universitat Politecnica de Valencia (UPV), under its R&D Support Program in PAID-01-10. TNO's work has been partially funded by European Community's Seventh Framework Programme (FP7/2007-2013) under Grant Agreement No. ICT-2011-8-318343 (STEER Project). CWI's work has been partially funded by the European Community's Seventh Framework Programme (FP7/2007-2013) under Grant Agreement No. ICT-2011-7-287723 (REVERIE Project).Montagud Aguar, M.; Boronat Segui, F.; Stokking, H.; Cesar, P. (2014). Design, Development and Assessment of Control Schemes for IDMS in a Standardized RTCP-based Solution. Computer Networks. 70:240-259. https://doi.org/10.1016/j.comnet.2014.06.004S2402597

Enhanced adaptive RTCP-based inter-destination multimedia synchronization approach for distributed applications

[EN] Newer social multimedia applications, such as Social TV or networked multi-player games, enable independent groups (or clusters) of users to interact among themselves and share services within the context of simultaneous media content consumption. In such scenarios, concurrently synchronized playout points must be ensured so as not to degrade the user experience on such interaction. We refer to this process as Inter-Destination Multimedia Synchronization (IDMS). This paper presents the design, implementation and evaluation of an evolved version of an RTCP-based IDMS approach, including an Adaptive Media Playout (AMP) scheme that aims to dynamically and smoothly adjust the playout timing of each one of the geographically distributed consumers in a specific cluster if an allowable asynchrony threshold between their playout states is exceeded. For that purpose, we previously had also to develop a full implementation of RTP/RTCP protocols for NS-2, in which we included the IDMS approach as an optional functionality. Simulation results prove the feasibility of such IDMS and AMP proposals, by adopting several dynamic master reference selection policies, to maintain an overall synchronization status (within allowable limits) in each cluster of participants, while minimizing the occurrence of long-term playout discontinuities (such as skips/pauses) which are subjectively more annoying and less tolerable to users than small variations in the media playout rate.This work has been financed, partially, by Universitat Politecnica de Valencia (UPV), under its R&D Support Program in PAID-05-11-002-331 Project and in PAID-01-10. Authors also would like to thank the anonymous reviewers that helped to significantly improve the quality of the paper with their constructive comments.Montagud, M.; Boronat, F. (2012). Enhanced adaptive RTCP-based inter-destination multimedia synchronization approach for distributed applications. Computer Networks. 56(12):2912-2933. https://doi.org/10.1016/j.comnet.2012.05.00329122933561