The hierarchical B picture coding is introduced into the extension of H.264/AVC in order to improve coding performance and provide temporal scalability as well. In general, coding performance is affected by the content variation in each GOP (Group of Picture). Therefore, the ways to determine the size of sun-GOP is a critical problem for video coding. In this thesis, the adaptive GOP structure determination scheme is proposed to select the appropriate sub-GOP size with content complexity consideration. We compute the frame difference by hierarchical B picture structure and use the information to be a basis of sub-GOP decision. Hence, we can get proper combination of sub-GOP. Experimental results show the RD curves that our proposed method compares with the fixed GOP setting in the existing hierarchical B picture coding of SVC.

Le champ du traitement des images et des vidéos attire l'attention depuis les deux dernières décennies. Ce champ couvre maintenant un spectre énorme d'applications comme la TV 3D, la télé-surveillance, la vision par ordinateur, l'imagerie médicale, la compression, la transmission, etc. En ce début de vingt et unième siècle nous sommes témoins d'une révolution importante. Les largeurs de bande des réseaux, les capacités de mémoire et les capacités de calcul ont été fortement augmentés durant cette période. Un client peut avoir un débit de plus de 100~mbps tandis qu'un autre peut utiliser une ligne à 56~kbps. Simultanément, un client peut avoir un poste de travail puissant, tandis que d'autres peuvent avoir juste un téléphone mobile. Au milieu de ces extrêmes, il y a des milliers de clients avec des capacités et des besoins très variables. De plus, les préférences d'un client doivent s'adapter à sa capacité, par exemple un client handicapé par sa largeur de bande peut être plus intéressé par une visualisation en temps réel sans interruption que d'avoir une haute résolution. Pour y faire face, des architectures hiérarchiques de codeurs vidéo ont été introduites afin de comprimer une seule fois, et de décomprimer de différentes manières. Comme la DCT n'a pas la fonctionnalité de multi-résolution, une architecture vidéo hiérarchique est conçue pour faire face aux défis des largeurs de bande et des puissances de traitement hétérogènes. Avec l'inondation des contenus numériques, qui peuvent être facilement copiés et modifiés, le besoin de la protection des contenus vidéo a pris plus d'importance. La protection de vidéos peut être réalisée avec l'aide de trois technologies : le tatouage de méta-données et l'insertion de droits d'auteur, le cryptage pour limiter l'accès aux personnes autorisées et la prise des empreintes digitales active pour le traçage de traître. L'idée principale dans notre travail est de développer des technologies de protection transparentes à l'utilisateur. Cela doit aboutir ainsi à un codeur vidéo modifié qui sera capable de coder et d'avoir un flux de données protégé. Puisque le contenu multimédia hiérarchique a déjà commencé à voir le jour, algorithmes pour la protection indépendante de couches d 'amélioration sont également proposées. / Field of image and video processing has got lot of attention during the last two decades. This field now covers a vast spectrum of applications like 3D TV, tele-surveillance, computer vision, medical imaging, compression, transmission and much more. Of particular interest is the revolution being witnessed by the first decade of twenty-first century. Network bandwidths, memory capacities and computing efficiencies have got revolutionized during this period. One client may have a 100~mbps connection whereas the other may be using a 56~kbps dial up modem. Simultaneously, one client may have a powerful workstation while others may have just a smart-phone. In between these extremes, there may be thousands of clients with varying capabilities and needs. Moreover, the preferences of a client may adapt to his capacity, e.g. a client handicapped by bandwidth may be more interested in real-time visualization without interruption than in high resolution. To cope with it, scalable architectures of video codecs have been introduced to 'compress once, decompress many ways' paradigm. Since DCT lacks the multi-resolution functionality, a scalable video architecture is designed to cope with challenges of heterogeneous nature of bandwidth and processing power. With the inundation of digital content, which can be easily copied and modified, the need for protection of video content has got attention. Video protection can be materialized with help of three technologies: watermarking for meta data and copyright insertion, encryption to restrict access to authorized persons, and active fingerprinting for traitor tracing. The main idea in our work is to make the protection technology transparent to the user. This would thus result in a modified video codec which will be capable of encoding and playing a protected bitstream. Since scalable multimedia content has already started coming to the market, algorithms for independent protection of enhancement layers are also proposed.

Veículos Aéreos não tripulados (VANTs) vêm sendo cada vez mais utilizados em diversos países, tanto na área militar como na civil. O cenário considerado nesse estudo é o de um VANT realizando captura de vídeo em tempo real, transmitindo-o a uma base terrestre por meio de rede sem fio. O problema consiste no fato de não ser possível garantir uma taxa de transmissão contínua, com banda estável. Isso ocorre devido a fatores como a velocidade da aeronave (da ordem centenas de km/h), irregularidades de terreno (impedindo a linha de visada do enlace de transmissão), ou do clima, como tempestades que podem interferir na transmissão da RF. Por fim, os movimentos que o VANT pode realizar no vôo (Rolagem, Arfagem ou Guinada) podem prejudicar a disponibilidade do link. Dessa forma, é necessário que seja realizada adaptação de vídeo de acordo com a banda disponível. Assim, quando a qualidade do enlace for degradada, deverá ser realizada uma redução no tamanho do vídeo, evitando a interrupção na transmissão. Por outro lado, a adaptação também deverá fazer com que a banda disponível seja utilizada, evitando o envio de vídeos com qualidade inferior à que seria possível para determinado valor de largura de banda. Nesse trabalho será considerada a faixa de valores de largura de banda de 8 Mbps até zero. Para realizar a adaptação será utilizado o padrão H.264/AVC com codificação escalável / Unmanned Aerial Vehicles (UAVs) are being increasingly used in several countries, both in the military and civilian areas. In this study we consider an UAV equipped with a camera, capturing video for a real-time transmission to a ground-base using wireless network. The problem is that its not possible to ensure a continuous transmission rate, with stable bandwidth. That occurs due to factors like the speed of the aircraft, irregularities of terrain, or the weather (as storms, heat and fog, for instance, can interfere with RF transmission). Finally, the movements that the UAV can perform in flight (Roll, pitch and yaw) can impair link availability. Thus, it is necessary to perform an adaptation of video according to the available bandwidth. When the link quality is degraded, a reduction in the resolution of the video must be performed , avoiding interruption of the transmission. Additionally, adaptation must also provide that all the available bandwidth is used, avoiding sending the video with lower quality that would be possible for a given value bandwidth. In this work we propose a system which can vary the total amount of data being transmitted, by adjusting the compression parameters of the video. We manage to produce a system which uses the range from 8 Mbps up to zero. We use the H.264/AVC Codec, with scalable video coding

Veículos Aéreos não tripulados (VANTs) vêm sendo cada vez mais utilizados em diversos países, tanto na área militar como na civil. O cenário considerado nesse estudo é o de um VANT realizando captura de vídeo em tempo real, transmitindo-o a uma base terrestre por meio de rede sem fio. O problema consiste no fato de não ser possível garantir uma taxa de transmissão contínua, com banda estável. Isso ocorre devido a fatores como a velocidade da aeronave (da ordem centenas de km/h), irregularidades de terreno (impedindo a linha de visada do enlace de transmissão), ou do clima, como tempestades que podem interferir na transmissão da RF. Por fim, os movimentos que o VANT pode realizar no vôo (Rolagem, Arfagem ou Guinada) podem prejudicar a disponibilidade do link. Dessa forma, é necessário que seja realizada adaptação de vídeo de acordo com a banda disponível. Assim, quando a qualidade do enlace for degradada, deverá ser realizada uma redução no tamanho do vídeo, evitando a interrupção na transmissão. Por outro lado, a adaptação também deverá fazer com que a banda disponível seja utilizada, evitando o envio de vídeos com qualidade inferior à que seria possível para determinado valor de largura de banda. Nesse trabalho será considerada a faixa de valores de largura de banda de 8 Mbps até zero. Para realizar a adaptação será utilizado o padrão H.264/AVC com codificação escalável / Unmanned Aerial Vehicles (UAVs) are being increasingly used in several countries, both in the military and civilian areas. In this study we consider an UAV equipped with a camera, capturing video for a real-time transmission to a ground-base using wireless network. The problem is that its not possible to ensure a continuous transmission rate, with stable bandwidth. That occurs due to factors like the speed of the aircraft, irregularities of terrain, or the weather (as storms, heat and fog, for instance, can interfere with RF transmission). Finally, the movements that the UAV can perform in flight (Roll, pitch and yaw) can impair link availability. Thus, it is necessary to perform an adaptation of video according to the available bandwidth. When the link quality is degraded, a reduction in the resolution of the video must be performed , avoiding interruption of the transmission. Additionally, adaptation must also provide that all the available bandwidth is used, avoiding sending the video with lower quality that would be possible for a given value bandwidth. In this work we propose a system which can vary the total amount of data being transmitted, by adjusting the compression parameters of the video. We manage to produce a system which uses the range from 8 Mbps up to zero. We use the H.264/AVC Codec, with scalable video coding

This study contributes to the domain of application specific adaptive hardware architectures with a design approach on processing element array, interconnect structure and memory interface concurrently. As summarized below, our architectural design choices push the limits of on-chip data reuse and avoid redundant computations that are essential for the high throughput, small area, and low power demands of the consumer market.Motion estimation (ME) is a key component in the H.264/AVC standard. Full Search (FS) based ME achieves optimal peak signal-to-noise-ratio (PSNR), and is the most adopted algorithm for developing hardware motion estimators. In this study, we first design a variable block size motion estimation (VBSME) engine based on hybrid grained processing elements (PEs) and a 2D programmable interconnect structure, which is adaptive to all block size configurations of H.264. PEs operate in bit-serial manner using MSB-first arithmetic for early termination to reduce the amount of computations, and the 2D architecture enables on-chip data reuse between neighboring PEs in a bit-by-bit pipelined fashion. Our design reduces the gate count by 7x compared to its ASIC counterpart, operates at a comparable frequency while sustaining 30 and 60 frames per second (fps); and outperforms bit parallel and bit serial architectures in terms of throughput and performance per gate.Numerous fast search algorithms (diamond, hexagon, three-step, etc.) have been developed to reduce the computation burden and the excessive amount of memory transactions required by FS, with a compromise in compression quality. We improve our VBSME engine and introduce the first adaptive ME architecture that provides the end user with the flexibility of choosing between the high quality video service during power-rich state (FS mode), and extended video service (fast search mode). We resolve the irregular indexing scheme challenge of three-step search (3SS) by introducing an on-chip buffer structure with a memory interface, which is adaptive to data access patterns of the FS and 3SS methods. The architecture sustains the real time CIF format (352x288) video encoding at 30fps with an operational frequency as low as 17.6MHz, and consumes 1.98mW based on the 45nm technology, outperforming all other FS and 3SS architectures.

This thesis proposes a strategy for enhancing the efficiency of scalable H.264/AVC video transmission over multi-input multi-output (MIMO) and cooperative communication systems. For scalable video coding (SVC) transmission over MIMO wireless systems, a channel selection algorithm is used to enhance transmission rate. The proposed algorithm allows SVC layers to select channels individually in wireless MIMO systems based on channel state information for transmission rate enhancement. Here, this difficult problem is converted into a mathematical optimization problem to improve SVC performance during video transmission. Experimental results show that the proposed method achieves a higher transmission rate over MIMO systems compared to the existing scheme. For SVC transmission over cooperative communication systems, the algorithm allows each SVC layer to choose an appropriate relay based on channel conditions and SVC layer priority. Thus, SVC data is protected effectively. Experimental results show that video quality obtained by the algorithm exceeds that of non-cooperative systems.

Scalable video coding (SVC) supports full scalability by extracting a partial bitstream to adapt to transmission and display requirements in multimedia applications. Most conventional video content is stored in non-scalable format, e.g., H.264/AVC, necessitating the development of an efficient video transcoding from a conventional format to a scalable one. This work describes a fast video transcoding architecture that overcomes the complexity of different coding structures between H.264/AVC and SVC. The proposed algorithm simplifies the mode decision process in SVC owing to its heavy computations. The current mode in SVC is selected by the highest conditional probability of SVC¡¦s mode given the H.264/AVC¡¦s mode. Exactly when an error prediction occurs is then detected using Bayesian theorem, followed by its refinement using the Markov model. Experimental results indicate that the proposed algorithm saves on average 75.28% of coding time with 0.13 dB PSNR loss over that when using a cascaded pixel domain transcoder.

In order to speedup the encoding process of H.264/AVC and Scalable Video Coding (SVC), Temporal and Spatial Correlation-based Merging and Splitting (TSCMS) fast mode decision algorithm and Coded Block Pattern (CBP)-based fast mode decision algorithm are proposed in this thesis. TSCMS and CBP-based fast mode decision algorithms are applied to H.264/AVC and SVC, respectively. In TSCMS, Temporal Correlation (TC) is used to predict the Motion Vectors (MVs) of 8¡Ñ8 blocks in each macroblock. In addition, the merging and splitting procedure is adopted to predict the motion vectors of other blocks. Afterwards, the spatial correlation is performed to merge 16¡Ñ16 blocks instead of the conventional merge scheme. CBP value is the syntax used at each Macroblock (MB) header to indicate whether an MB contains residual information or not in CBP-based fast mode decision algorithm. The proposed algorithm can exclude the invalid modes for the mode prediction of the current MB in Enhancement Layer (EL) through the CBP values and MB modes of adjacent MBs in EL and the co-located Base Layer (BL) MB modes. Experimental results show that the proposed algorithms reduce computations significantly with negligible PSNR degradation and bit increase when compared to JM 12.3, JSVM 9.12, and the other existing methods.

ITC/USA 2012 Conference Proceedings / The Forty-Eighth Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2012 / Town and Country Resort & Convention Center, San Diego, California / In this paper, a novel zigzag scanning concept of quantized coefficients for H.264/AVC is introduced. In order to scan the quantized coefficients efficiently, the statistical occurrence values of the quantized coefficients after the final mode decision are utilized. We develop a zigzag scanning pattern by reordering the statistical occurrence values in descending order. In addition, we consider the temporal and spatial correlation among the frames to classify the zigzag scanning pattern. In particular, we focus on the macroblock level zigzag scanning so that the proposed method will have the different zigzag scanning pattern based on the macroblock. Experimental results show that the proposed scheme reduces the total bits up to 4.05% and 3.67% while introducing either negligible loss of video quality for intra- and inter mode, respectively.

De nos jours, les vidéos et les images sont devenues un moyen de communication très important. L'acquisition, la transmission, l'archivage et la visualisation de ces données visuelles, que ce soit à titre professionnel ou privé, augmentent de manière exponentielle. En conséquence, la confidentialité de ces contenus est devenue un problème majeur. Pour répondre à ce problème, le chiffrement sélectif est une solution qui assure la confidentialité visuelle des données en ne chiffrant qu'une partie des données. Le chiffrement sélectif permet de conserver le débit initial et de rester conforme aux standards vidéo. Ces travaux de thèse proposent plusieurs méthodes de chiffrement sélectif pour le standard vidéo H.264/AVC. Des méthodes de réduction du chiffrement sélectif grâce à l'architecture du standard H.264/AVC sont étudiées afin de trouver le ratio de chiffrement minimum mais suffisant pour assurer la confidentialité visuelle des données. Les mesures de qualité objectives sont utilisées pour évaluer la confidentialité visuelle des vidéos chiffrées. De plus, une nouvelle mesure de qualité est proposée pour analyser le scintillement des vidéos au cours du temps. Enfin, une méthode de chiffrement sélectif réduit régulé par des mesures de qualité est étudiée afin d'adapter le chiffrement en fonction de la confidentialité visuelle fixée. / Nowadays, videos and images are major sources of communication for professional or personal purposes. Their number grow exponentially and the confidentiality of the content has become a major problem for their acquisition, transmission, storage, and display. In order to solve this problem, selective encryption is a solution which provides visual privacy by encrypting only a part of the data. Selective encryption preserves the initial bit-rate and maintains compliance with the syntax of the standard video. This Ph.D thesis offers several methods of selective encryption for H.264/AVC video standard. Reduced selective encryption methods, based on the H.264/AVC architecture, are studied in order to find the minimum ratio of encryption but sufficient to ensure visual privacy. Objective quality measures are used to assess the visual privacy of encrypted videos. In addition, a new quality measure is proposed to analyze the video flicker over time. Finally, a method for a reduced selective encryption regulated by quality measures is studied to adapt the encryption depending on the visual privacy fixed.