Digital video is a popular technology used in many different applications. The quality of video, expressed in the spatial and temporal resolution, has been increasing continuously in the last years. In order to reduce the bitrate required for its storage and transmission, a new generation of video encoders and decoders (codecs) have been developed. The latest video codec standard, known as H.264/AVC, includes sophisticated compression tools that require more computing resources than any previous video codec. The combination of high quality video and the advanced compression tools found in H.264/AVC has resulted in a significant increase in the computational requirements of video decoding applications. The main objective of this thesis is to provide the performance required for real-time operation of high quality video decoding using programmable architectures. Our solution has been the simultaneous exploitation of multiple levels of parallelism. On the one hand, video decoders have been modified in order to extract as much parallelism as possible. And, on the other hand, general purpose architectures has been enhanced for exploiting the type of parallelism that is present in video codec applications. / El vídeo digital es una tecnología popular utilizada en una gran variedad de aplicaciones. La calidad de vídeo, expresada en la resolución espacial y temporal, ha ido aumentando constantemente en los últimos años. Con el fin de reducir la tasa de bits requerida para su almacenamiento y transmisión, se ha desarrollado una nueva generación de codificadores y decodificadores (códecs) de vídeo. El códec estándar de vídeo más reciente, conocido como H.264/AVC, incluye herramientas sofisticadas de compresión que requieren más recursos de computación que los códecs de vídeo anteriores. El efecto combinado del vídeo de alta calidad y las herramientas de compresión avanzada incluidas en el H.264/AVC han llevado a un aumento significativo de los requerimientos computacionales de la decodificación de vídeo. El objetivo principal de esta tesis es proporcionar el rendimiento necesario para la decodificación en tiempo real de vídeo de alta calidad. Nuestra solución ha sido la explotación simultánea de múltiples niveles de paralelismo. Por un lado, se realizaron modificaciones en el decodificador de vídeo con el fin de extraer múltiples niveles de paralelismo. Y, por otro lado, se modificaron las arquitecturas de propósito general para mejorar la explotación del tipo paralelismo que está presente en las aplicaciones de vídeo. Primero hicimos un análisis de la escalabilidad de dos extensiones de Instrucción Simple con Múltiples Datos (SIMD por sus siglas en inglés): una de una dimensión (1D) y otra matricial de dos dimensiones (2D). Se demostró que al escalar la extensión 2D se obtiene un mayor rendimiento con una menor complejidad que al escalar la extensión 1D. Luego se realizó una caracterización de la decodificación de H.264/AVC en aplicaciones de alta definición (HD) donde se identificaron los núcleos principales. Debido a la falta de un punto de referencia (benchmark) adecuado para la decodificación de vídeo HD, desarrollamos uno propio, llamado HD-VideoBench el cual incluye aplicaciones completas de codificación y decodificación de vídeo junto con una serie de secuencias de vídeo en HD. Después optimizamos los núcleos más importantes del decodificador H.264/AVC usando instrucciones SIMD. Sin embargo, los resultados no alcanzaron el máximo rendimiento posible debido al efecto negativo de la desalineación de los datos en memoria. Como solución, evaluamos el hardware y el software necesarios para realizar accesos no alineados. Este soporte produjo mejoras significativas de rendimiento en la aplicación. Aparte se realizó una investigación sobre cómo extraer paralelismo de nivel de tarea. Se encontró que ninguno de los mecanismos existentes podía escalar para sistemas masivamente paralelos. Como alternativa, desarrollamos un nuevo algoritmo que fue capaz de encontrar miles de tareas independientes al explotar paralelismo de nivel de macrobloque. Luego implementamos una versión paralela del decodificador de H.264 en una máquina de memoria compartida distribuida (DSM por sus siglas en inglés). Sin embargo esta implementación no alcanzó el máximo rendimiento posible debido al impacto negativo de las operaciones de sincronización y al efecto del núcleo de decodificación de entropía. Con el fin de eliminar estos cuellos de botella se evaluó la paralelización al nivel de imagen de la fase de decodificación de entropía combinada con la paralelización al nivel de macrobloque de los demás núcleos. La sobrecarga de las operaciones de sincronización se eliminó casi por completo mediante el uso de operaciones aceleradas por hardware. Con todas las mejoras presentadas se permitió la decodificación, en tiempo real, de vídeo de alta definición y alta tasa de imágenes por segundo. Como resultado global se creó una solución escalable capaz de usar el número creciente procesadores en las arquitecturas multinúcleo.

At Saab Aerosystems, situated in Linköping Sweden, there is a presentation and manoeuvre simulator simulating the fighter jet JAS-39 Gripen. This flight simulator is called PMSIM. In this thesis we study how to transfer sensor images generated by PMSIM to other simulators or desktop computers. The transmission is band-limited so some kind of image coding must be used. Because of this the greater part of this thesis is concerned with image coding. To fulfill the real time requirement the image coding has to be quite simple and the transmission has to be fast. To achieve fast transmission the network protocol has to use as little overhead information as possible. Such a protocol has therefore been designed and implemented. This report also includes a survey about real radio links. This survey investigates how the quality of the video stream can be affected by noise and other disturbing elements. The work in this report revolves around the implementation of a video link. The purpose of this link is to transmit and display sensor images. The link consists mainly of the three following parts: image coder, network link and image player. The image coding has been focused on MPEG and wavelets. The wavelet technique is not a well known coding principle for video applications. Although as a coding technique for still images the technique is well known. For instance it is used in the JPEG2000-standard. Experiments conducted and published in this report suggest that for some applications the wavelet technique can be a viable candidate, with respect to the MPEG technique, for a video coder.

This thesis describes the design and implementation of a Digital Audio Broadcasting (DAB) System developed using C++ Language and SystemC libraries. The main aspects covered within this report are the data structure of DAB system, and some interesting points of SystemC Library very useful for the implementation of the final system. It starts with a introduction of DAB system and his principals advantages. Next it goes further into the definition of data structures of DAB, they are FIC, MSC, and DAB audio frame, explained with MPEG and PAD packets. Later on this chapter there is an explanation of the SystemC library with special attention on the features that I used to implement the system. This features are the events used in the communication between processes and the interfaces needed for sending and receiving the data. With all these points covered is quite easy for a reader to understand the implementation of the system, despite this point is covered in the last chapter of the thesis. The implementation is here explained in two different steps. The first one explain how is formed the DAB audio frame by means of MPEG frames that are wrote in channel by producer interface, this frames are readed by consumer interface. For this purpose I have created some classes and structures that are explained in this part. The second part explain how I obtain the DAB transmission frame which is obtained creating MSC frames, that are big data structures formed by groups of DAB audio frames, therefore there are some functions that act like a buffer and add audio frames to the MSC data structure. Of independent way there is the FIC frame that is generated of random way and its added to the transmission frame.

The increase in the use of digital video/image has showed the need for modeling and querying the semantic content in them. Using manual annotation techniques for defining the semantic content is both costly in time and have limitations on querying capabilities. So, the need for content based information retrieval in multimedia domain is to extract the semantic content in an automatic way. The semantic content is usually defined with the objects in images/videos. In this thesis, a Genetic Algorithm based object extraction and classification mechanism is proposed for extracting the content of the videos and images. The object extraction is defined as a classification problem and a Genetic Algorithm based classifier is proposed for classification. Candidate objects are extracted from videos/images by using Normalized-cut segmentation and sent to the classifier for classification. Objects are defined with the Best Representative and Discriminative Feature (BRDF) model, where features are MPEG-7 descriptors. The decisions of the classifier are calculated by using these features and BRDF model. The classifier improves itself in time, with the genetic operations of GA. In addition to these, the system supports fuzziness by making multiple categorization and giving fuzzy decisions on the objects. Externally from the base model, a statistical feature importance determination method is proposed to generate BRDF model of the categories automatically. In the thesis, a platform independent application for the proposed system is also implemented.

Video databases and content based retrieval in these databases have become popular with the improvements in technology. Metadata extraction techniques are used for providing data to video content. One popular metadata extraction technique for mul- timedia is information extraction from text. For some domains, it is possible to &amp / #64257 / nd accompanying text with the video, such as soccer domain, movie domain and news domain. In this thesis, we present an approach of metadata extraction from match reports for soccer domain. The UEFA Cup and UEFA Champions League Match Reports are downloaded from the web site of UEFA by a web-crawler. These match reports are preprocessed by using regular expressions and then important events are extracted by using hand-written rules. In addition to hand-written rules, two di&amp / #64256 / erent machine learning techniques are applied on match corpus to learn event patterns and automatically extract match events. Extracted events are saved in an MPEG-7 &amp / #64257 / le. A user interface is implemented to query the events in the MPEG-7 match corpus and view the corresponding video segments.

Thèse doctorat : Instrumentation et Micro-Electronique : Nancy 1 : 2006. / Titre provenant de l'écran-titre.

Thesis (M. S.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2008. / Committee Chair: Bing Benny; Committee Co-Chair: Fred B-H. Juang; Committee Member: Gee-Kung Chang. Part of the SMARTech Electronic Thesis and Dissertation Collection.

Cette thèse a pour objectif d'étudier et d'analyser une nouvelle stratégie de compression, dont le principe consiste à compresser conjointement des données issues de plusieurs modalités, en utilisant un codeur unique. Cette approche est appelée " Compression Multimodale ". Dans ce contexte, une image et un signal audio peuvent être compressés conjointement et uniquement par un codeur d'image (e.g. un standard), sans la nécessité d'intégrer un codec audio. L'idée de base développée dans cette thèse consiste à insérer les échantillons d'un signal en remplacement de certains pixels de l'image " porteuse " tout en préservant la qualité de l'information après le processus de codage et de décodage. Cette technique ne doit pas être confondue aux techniques de tatouage ou de stéganographie puisqu'il ne s'agit pas de dissimuler une information dans une autre. En Compression Multimodale, l'objectif majeur est, d'une part, l'amélioration des performances de la compression en termes de débit-distorsion et d'autre part, l'optimisation de l'utilisation des ressources matérielles d'un système embarqué donné (e.g. accélération du temps d'encodage/décodage). Tout au long de ce rapport, nous allons étudier et analyser des variantes de la Compression Multimodale dont le noyau consiste à élaborer des fonctions de mélange et de séparation, en amont du codage et de séparation. Une validation est effectuée sur des images et des signaux usuels ainsi que sur des données spécifiques telles que les images et signaux biomédicaux. Ce travail sera conclu par une extension vers la vidéo de la stratégie de la Compression Multimodale

In this thesis, a mixed type video segmentation algorithm is implemented to find the scene cuts in MPEG compressed video data. The main aim is to have a computationally efficient algorithm for real time applications. Due to this reason partial decoding of the bitstream is used in segmentation. As a result of partial decoding, features such as bitrate, motion vector type, and DC images are implemented to find both continuous and discontinuous scene cuts on a MPEG-2 coded general TV broadcast data. The results are also compared with techniques found in literature.

In this thesis, a Content Based Image Retrieval (CBIR) system to query the objects in an image database is proposed. Images are represented as collections of regions after being segmented with Normalized Cuts algorithm. MPEG-7 content descriptors are used to encode regions in a 239-dimensional feature space. User of the proposed CBIR system decides which objects to query and labels exemplar regions to train the system using a graphical interface. Fuzzy ARTMAP algorithm is used to learn the mapping between feature vectors and binary coded class identification numbers. Preliminary recognition experiments prove the power of fuzzy ARTMAP as a region classifier. After training, features of all regions in the database are extracted and classified. Simple index files enabling fast access to all regions from a given class are prepared to be used in the querying phase. To retrieve images containing a particular object, user opens an image and selects a query region together with a label in the graphical interface of our system. Then the system ranks all regions in the indexed set of the query class with respect to their L2 (Euclidean) distance to the query region and displays resulting images. During retrieval experiments, comparable class precisions with respect to exhaustive searching of the database are maintained which demonstrates e ectiveness of the classifier in narrowing down the search space.