DigitalF: Angewandte Informatik
Beitrag (Sammelband oder Tagungsband)
Y. Pitrey, Marcus Barkowsky, R. Pépion, P. Le Callet, H. Hlavacs
Influence of the source content and encoding configuration on the preceived quality for scalable video coding
Proceedings of SPIE Vol. 8291: Human Vision and Electronic Imaging XVII, San Francisco, CA, USA, no. 54
In video coding, it is commonly accepted that the encoding paramaters such as the quantization step-size have an influence on the perceived quality. When dealing with Scalable Video Coding (SVC), the parameters used to encode each layer logically have an influence on the overall perceived quality. It is also commonly accepted that using given encoding parameters, the perceived quality does not change significantly according to the encoded source content. In this paper, we evaluate the impact of both SVC coding artifacts and source contents on the quality perceived by human observers. We exploit the outcomes of two subjective experiments designed and conducted under standard conditions in order to provide reliable results. The two experiments are aligned on a common scale using a set of shared processed video sequences, resulting in a database containing the subjective scores for 60 different sources combined with 20 SVC scenarios. We analyse the performance of several source descriptors in modeling the relative behaviour of a given source content when compared to the average of other source contents.
F: Elektrotechnik und Medientechnik
Andreas Berl, H. Meer, H. Hlavacs, T. Treutner
Virtualization in Energy-Efficient Future Home Environments
IEEE Communications Magazine, vol. 47, no. Dezember, pp. 62-67
Home environments promise high potential in terms of resource sharing and energy saving. More and more home computers are running on an always-on basis (e.g., media centers or file sharing clients). Such home environments have not been sufficiently analyzed regarding the possibility of aggregating home user resources in an energy-efficient way. This article describes a future home environment in which available hardware resources (e.g., CPU cycles, disk space, or network capacity) are shared energy efficiently and balanced among end users. Furthermore, the article provides an overview of different virtualization methods that are needed in future home environments to enable cooperation of home networks. Virtualization-related requirements are discussed in detail and virtualization methods and concepts are compared to each other with respect to their usability in the architecture.
F: Elektrotechnik und Medientechnik
H. Hlavacs, K. Hummel, R. Weidlich, A. Houyou, Andreas Berl, H. Meer
Distributed Energy Efficiency in Future Home Environments
Annals of Telecommunications (Special issue: Next Generation Network and Service Management), vol. 63, no. Oktober, pp. 473-485
In this paper, a new architecture for sharing resources among home environments is proposed. Our approach goes far beyond traditional systems for distributed virtualization, like PlanetLab or grid computing, as it relies on complete decentralization in a peer-to-peer (P2P) like manner and, above all, aims at energy efficiency. Energy metrics are defined, which have to be optimized by the system. The system itself uses virtualization to transparently move tasks from one home to another to optimally utilize the existing computing power. We present an overview of our proposed architecture, consisting of a middleware interconnecting computers and routers in possibly millions of homes using P2P techniques. For demonstrating the potential energy saving of distributed applications, we present an analytical model for sharing downloads, which is verified by discrete event simulation. The model represents an optimistic case without P2P overhead and fairness. The model allows to assess the upper limit of the saving potential. An enhanced version of the simulation model also shows the effect of fairness. The fairer the system gets, the less efficient it is.