Publicación: Análisis de prestaciones para servicios multimedia masivos y su aplicación a sistemas de distribución de vídeo adaptativos
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2016
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Atribución-NoComercial-SinDerivadas 4.0 Internacional
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Universidad Nacional de Educación a Distancia (España). Escuela Internacional de Doctorado. Programa de Doctorado en Tecnologías Industriales
Resumen
En los últimos años, la proliferación de servicios de vídeo en Internet, la expansión del mercado a un público masivo y un aumento notable de las calidades de los flujos multimedia involucrados son hechos constatados. La tecnología avanza más rápido que el mercado y con frecuencia surgen nuevos paradigmas en el diseño y la ejecución de los servicios de video. Las compañías realizan grandes esfuerzos por adaptarse a la demanda creciente e incorporar las tecnologías emergentes, dedicando tiempo y esfuerzo a evaluar, y mejorar, las prestaciones de sus servicios. La popularidad de los servicios de vídeo adaptativos es sólo un ejemplo de las posibilidades que se abren con las mejoras en la tecnología, en este caso de codificadores escalables. Se habilitan los diseños de nuevos servicios basados en estos paradigmas escalables y se abre un nuevo ciclo de vida para éstos. Pero la evaluación de las prestaciones de los servicios es un concepto muy amplio que esconde varios retos. La primera contrariedad de la evaluación de los servicios multimedia en situaciones heterogéneas es la enorme dificultad de disponer de los escenarios adecuados para la reproducción de las condiciones deseadas. En muchos casos, la evaluación de servicios debe realizarse de distintas formas según la fase de su desarrollo. Entre la simulación inicial y el despliegue real del servicio el proceso de evaluación pasa por distintas fases que implican el conocimiento y la aplicación de técnicas diferentes. Además, las medidas realizadas sobre el desempeño del servicio deben realizarse en base a algún criterio objetivo, acreditado y comparable. En este sentido las métricas de calidad de vídeo han surgido de forma natural evolucionando desde los mismos modelos que se venían aplicando a las imágenes. Otras técnicas más avanzadas han ido incorporando las características intrínsecas del contenido de vídeo, más allá de la pura definición de secuencias de imágenes, para reflejar con un criterio más adecuado la calidad del servicio multimedia. Como paso natural a la evaluación del servicio multimedia, la opinión del usuario ha sido incorporada como una métrica altamente importante de cara a considerar todos los factores determinantes en el servicio extremo a extremo, o end-to-end. En esta tesis se hacen una serie de contribuciones en los tres ejes principales descritos en este resumen. Para la evaluación de servicios se han explorado técnicas de simulación, en particular centrándose en simulación en tiempo real y se ha propuesto una metodología para la construcción de entornos de experimentación enfocada en servicios masivos. Para la evaluación de los servicios en las primeras etapas se recurre con frecuencia a las métricas de calidad objetivas. En este trabajo se han investigado y desarrollado herramientas que permiten la medición de estas métricas en el ámbito de los flujos multimedia escalables y adaptativos. Finalmente se han realizado dos estudios de campo con la participación de más de 170 usuarios en total, evaluando distintos aspectos de la calidad percibida de los sistemas de multimedia en general y vídeos adaptativos en particular. El trabajo original concluye las aportaciones realizando una serie de propuestas para la ejecución de las fases de diseño y evaluación de los sistemas multimedia adaptativos. Esta tesis doctoral se enmarca en una línea de investigación sobre sistemas multimedia abierta en el grupo de investigación DMMS de la Universidad de Oviedo, en colaboración según el acuerdo marco con el grupo del Departamento de Ingeniería Eléctrica Electrónica y Control de la UNED.
In recent years, the proliferation of Internet video services, expanding the market to a mass audience and a significant increase in the quality of multimedia streams involved are established facts. Technology advances faster than the market and new paradigms often arise in the design and implementation of video services. Companies make great efforts to adapt to the growing demand and incorporate emerging technologies, devoting time and effort to evaluate and improve the performance of their services. The popularity of adaptive video services is just one example of the possibilities open thanks to improvements made in technology, in this case of scalable encoders. New service designs based on scalable paradigms are enabled and a new life cycle for these services opens. But the evaluation of the performance of services is a very broad concept that hides several challenges. The first setback of the evaluation of multimedia services in heterogeneous situations is the enormous difficulty of having the appropriate settings for playing the desired conditions. In many cases, the evaluation of services must be performed in different ways depending on the stage of development. Between the initial simulation and actual deployment of the service, the assessment process goes through various stages that involve knowledge and application of different techniques. In addition, measurements on service performance should be made based on some objective criteria, accredited and comparable. In this sense, the video quality metrics have emerged, naturally evolved from the same models that had applied to images. More advanced techniques have been incorporating the intrinsic characteristics of video content, beyond the pure definition image sequences to reflect a more appropriate criterion quality multimedia service. As a natural step to assessing the multimedia service, user opinion has been incorporated as a highly important metric face to consider all the factors in the service end-to-end or end-to-end. In this thesis a series of contributions are made in three main areas described in this summary. For the evaluation of services simulation techniques, including focusing on realtime simulation have been explored. A methodology for building experimental environments focused on mass services has been proposed. For the evaluation of services in the early stages are used frequently objective quality metrics. In this paper we have researched and developed tools for measuring these metrics in the field of adaptive and scalable multimedia streams. Finally there have been two field studies involving more than 170 users in total, evaluating different aspects of perceived quality of multimedia systems in general and adaptive videos in particular. The original work concludes making a series of proposals for the implemmentation of design and evaluation phases of adaptive multimedia systems. This thesis is part of a research on multimedia systems open with DMMS research group at the University of Oviedo, in cooperation with the group of the Department of Electronics and Electrical Engineering Control at UNED.
In recent years, the proliferation of Internet video services, expanding the market to a mass audience and a significant increase in the quality of multimedia streams involved are established facts. Technology advances faster than the market and new paradigms often arise in the design and implementation of video services. Companies make great efforts to adapt to the growing demand and incorporate emerging technologies, devoting time and effort to evaluate and improve the performance of their services. The popularity of adaptive video services is just one example of the possibilities open thanks to improvements made in technology, in this case of scalable encoders. New service designs based on scalable paradigms are enabled and a new life cycle for these services opens. But the evaluation of the performance of services is a very broad concept that hides several challenges. The first setback of the evaluation of multimedia services in heterogeneous situations is the enormous difficulty of having the appropriate settings for playing the desired conditions. In many cases, the evaluation of services must be performed in different ways depending on the stage of development. Between the initial simulation and actual deployment of the service, the assessment process goes through various stages that involve knowledge and application of different techniques. In addition, measurements on service performance should be made based on some objective criteria, accredited and comparable. In this sense, the video quality metrics have emerged, naturally evolved from the same models that had applied to images. More advanced techniques have been incorporating the intrinsic characteristics of video content, beyond the pure definition image sequences to reflect a more appropriate criterion quality multimedia service. As a natural step to assessing the multimedia service, user opinion has been incorporated as a highly important metric face to consider all the factors in the service end-to-end or end-to-end. In this thesis a series of contributions are made in three main areas described in this summary. For the evaluation of services simulation techniques, including focusing on realtime simulation have been explored. A methodology for building experimental environments focused on mass services has been proposed. For the evaluation of services in the early stages are used frequently objective quality metrics. In this paper we have researched and developed tools for measuring these metrics in the field of adaptive and scalable multimedia streams. Finally there have been two field studies involving more than 170 users in total, evaluating different aspects of perceived quality of multimedia systems in general and adaptive videos in particular. The original work concludes making a series of proposals for the implemmentation of design and evaluation phases of adaptive multimedia systems. This thesis is part of a research on multimedia systems open with DMMS research group at the University of Oviedo, in cooperation with the group of the Department of Electronics and Electrical Engineering Control at UNED.
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Facultades y escuelas::E.T.S. de Ingenieros Industriales