Toward a General Parametric Model for Assessing the Impact of Video Transcoding on Objective Video Quality

Video transcoding can cause degradation to an original video. Currently, there is no general model that assesses the impact of video transcoding on video quality. Such a model could play a critical role in evaluating the quality of the transcoded video, and thereby optimizing delivery of video to end-users while meeting their expectations. The main contribution of this research is the development and substantiation of a general parametric model, called the Video Transcoding Objective-quality Model (VTOM), that provides an extensible video transcoding service selection mechanism, which takes into account both the format and characteristics of the original video and the desired output, i.e., viewing format with preferred quality of service. VTOM represents a mathematical function that uses a set of media-related parameters for the original video and desired output, including codec, bit rate, frame rate, and frame size to predict the quality of the transcoded video generated from a specific transcoding. VTOM includes four quality sub-models, each describing the impact of each of these parameters on objective video quality, as well as a weighted-product aggregation function that combines these quality sub-models with four additional error sub-models in a single function for assessing the overall video quality. I compared the predicted quality results generated from the VTOM with quality values generated from an existing objective-quality metric. These comparisons yielded results that showed good correlations, with low error values. VTOM helps the researchers and developers of video delivery systems and applications to calculate the degradation that video transcoding can cause on the fly, rather than evaluate it statistically using statistical methods that only consider the desired output. Because VTOM takes into account the quality of the input video, i.e., video format and characteristics, and the desired quality of the output video, it can be used for dynamic video transcoding service selection and composition. A number of quality metrics were examined and used in development of VTOM and its assessment. However, this research discovered that, to date, there are no suitable metrics in the literature for comparing two videos with different frame rates. Therefore, this dissertation defines a new metric, called Frame Rate Metric (FRM) as part of its contributions. FRM can use any frame-based quality metric for comparing frames from both videos. Finally, this research presents and adapts four Quality of Service (QoS)-aware video transcoding service selection algorithms. The experimental results showed that these four algorithms achieved good results in terms of time complexity, success ratio, and user satisfaction rate

Puppeteer: Component-based Adaptation for Mobile Computing

Puppeteer is a system for adapting component-based applications in mobile environments. Puppeteer takes advantage of the exported interfaces of these applications and the structured nature of the documents they manipulate to perform adaptation without modifying the applications. The system is structured in a modular fashion, allowing easy addition of new applications and adaptation policies. Our initial prototype focuses on adaptation to limited bandwidth. It runs on Windows NT, and includes support for a variety of adaptation policies for Microsoft PowerPoint and Internet Explorer 5. We demonstrate that Puppeteer can support complex policies without any modification to the application and with little overhead. To the best of our knowledge, previous implementations of adaptations of this nature have relied on modifying the application

Optimising Networks For Ultra-High Definition Video

The increase in real-time ultra-high definition video services is a challenging issue for current network infrastructures. The high bitrate traffic generated by ultra-high definition content reduces the effectiveness of current live video distribution systems. Transcoders and application layer multicasting (ALM) can reduce traffic in a video delivery system, but they are limited due to the static nature of their implementations. To overcome the restrictions of current static video delivery systems, an OpenFlow based migration system is proposed. This system enables an almost seamless migration of a transcoder or ALM node, while delivering real-time ultra-high definition content. Further to this, a novel heuristic algorithm is presented to optimise control of the migration events and destination. The combination of the migration system and heuristic algorithm provides an improved video delivery system, capable of migrating resources during operation with minimal disruption to clients. With the rise in popularity of consumer based live streaming, it is necessary to develop and improve architectures that can support these new types of applications. Current architectures introduce a large delay to video streams, which presents issues for certain applications. In order to overcome this, an improved infrastructure for delivering real-time streams is also presented. The proposed system uses OpenFlow within a content delivery network (CDN) architecture, in order to improve several aspects of current CDNs. Aside from the reduction in stream delay, other improvements include switch level multicasting to reduce duplicate traffic and smart load balancing for server resources. Furthermore, a novel max-flow algorithm is also presented. This algorithm aims to optimise traffic within a system such as the proposed OpenFlow CDN, with the focus on distributing traffic across the network, in order to reduce the probability of blocking

Network Slices for Vertical Industries

Network Slicing allows to simultaneously support the specific needs of vertical industries with a diverse range of networking and computing requirements. Network Functions Virtualization (NFV) has been defined to deploy multiple network services on a common infrastructure. We extend the NFV concept to vertical services, i.e. services implemented on top of network services and providing the applications of the verticals. We present a component of the 5G-Transformer system, named vertical slicer, which acts as the interface to verticals. The vertical slicer has two main functionalities: allowing verticals to define vertical services based on a set of service blueprints and arbitrating among several vertical services in case of resource shortage.This work has been partially funded by the EU H2020 5G-Transformer Project (grant no. 761536

The Distribution Function: at the Heart of managing Cultural-Product Industries

Cultural industries (music, publishing, movies, television) faced similar trends in recent years : growing importance of distribution, raising costs in promotion, concentrating demand on fewer products, restructuring value added chain. Internet was considered, at a given time, as a lever to promote diversity and to support an expanding creation ; on a contrary, its development contributed to increase concentration and give more importance to prescription and distribution portals. Our communication aims at analyzing precisely the role of distributors in the chain value of cultural industries : aggregating demand, prescribing cultural goods to consumers, contractor for producers. We study distribution comparing more specifically three models of cultural industries : book publishing, movie theaters and television. These models provide with a conceptual framework considering distribution as a network structure. They help to report trends at stake in cultural industries : mass distribution and dematerialization, transforming business models...distribution