La présente thèse aborde le sujet de tatouage du flux MPEG-4 AVC sur ses deux volets théoriques et applicatifs en considérant deux domaines applicatifs à savoir la protection du droit d’auteur et la vérification de l'intégrité du contenu. Du point de vue théorique, le principal enjeu est de développer un cadre de tatouage unitaire en mesure de servir les deux applications mentionnées ci-dessus. Du point de vue méthodologique, le défi consiste à instancier ce cadre théorique pour servir les applications visées. La première contribution principale consiste à définir un cadre théorique pour le tatouage multi symboles à base de modulation d’index de quantification (m-QIM). La règle d’insertion QIM a été généralisée du cas binaire au cas multi-symboles et la règle de détection optimale (minimisant la probabilité d’erreur à la détection en condition du bruit blanc, additif et gaussien) a été établie. Il est ainsi démontré que la quantité d’information insérée peut être augmentée par un facteur de log2m tout en gardant les mêmes contraintes de robustesse et de transparence. Une quantité d’information de 150 bits par minutes, soit environ 20 fois plus grande que la limite imposée par la norme DCI est obtenue. La deuxième contribution consiste à spécifier une opération de prétraitement qui permet d’éliminer les impactes du phénomène du drift (propagation de la distorsion) dans le flux compressé MPEG-4 AVC. D’abord, le problème a été formalisé algébriquement en se basant sur les expressions analytiques des opérations d’encodage. Ensuite, le problème a été résolu sous la contrainte de prévention du drift. Une amélioration de la transparence avec des gains de 2 dB en PSNR est obtenue / The present thesis addresses the MPEG-4 AVC stream watermarking and considers two theoretical and applicative challenges, namely ownership protection and content integrity verification.From the theoretical point of view, the thesis main challenge is to develop a unitary watermarking framework (insertion/detection) able to serve the two above mentioned applications in the compressed domain. From the methodological point of view, the challenge is to instantiate this theoretical framework for serving the targeted applications. The thesis first main contribution consists in building the theoretical framework for the multi symbol watermarking based on quantization index modulation (m-QIM). The insertion rule is analytically designed by extending the binary QIM rule. The detection rule is optimized so as to ensure minimal probability of error under additive white Gaussian noise distributed attacks. It is thus demonstrated that the data payload can be increased by a factor of log2m, for prescribed transparency and additive Gaussian noise power. A data payload of 150 bits per minute, i.e. about 20 times larger than the limit imposed by the DCI standard, is obtained. The thesis second main theoretical contribution consists in specifying a preprocessing MPEG-4 AVC shaping operation which can eliminate the intra-frame drift effect. The drift represents the distortion spread in the compressed stream related to the MPEG encoding paradigm. In this respect, the drift distortion propagation problem in MPEG-4 AVC is algebraically expressed and the corresponding equations system is solved under drift-free constraints. The drift-free shaping results in gain in transparency of 2 dB in PSNR

Cette thèse a pour ambition d’explorer d’un point de vue théorique et applicatif le paradigme de l’in-band enrichment. Emergence de la société des connaissances, le concept de média enrichi renvoie à toute association de métadonnée (textuelle, audiovisuelle, code exécutable) avec un média d’origine. Un tel principe peut être déployé dans une large variété d’applications comme la TVNi - Télévision Numérique interactive, les jeux ou la fouille des données. Le concept de l’inband enrichement conçu et développé par M. Mitrea et son équipe au Département ARTEMIS de Télécom SudParis, suppose que les données d’enrichissement sont insérées dans le contenu même à enrichir. Ainsi, un tel concept peut-il tirer parti de techniques de tatouage, dès lors que celles-ci démontrent qu’elles ont la capacité d’insérer la quantité d’information requise par ce nouveau type d’application : i.e. 10 à 1000 fois plus grande que celle nécessaire pour les enjeux d’authentification ou de protection de droit d’auteur. Si par tradition la marque est insérée dans le domaine non compressé, les contraintes relatives aux nombreuses applications émergentes (comme la VoD – Vidéo à la Demande ou la TVNi) font du tatouage en temps réel dans le domaine compressé un important défi théorique et applicatif. Cependant, le tatouage dans le domaine compressé est une alliance de mots contradictoires puisque la compression (élimination de la redondance) rend l’hôte plus sensible aux modifications et l’association hôte/marque, plus fragile / The present thesis, developed at Institut Télécom Télécom SudParis under the “Futur et Rupture” framework, takes the challenge of exploring from both theoretical and applicative points of views the in band enrichment paradigm. Emerged with the knowledge society, the enriched media refers to any type of association which may be established between some metadata (textual, audio, video, exe codes...) and a given original media. Such a concept is currently deployed in a large variety of applications like the iDTV (interactive Digital TV), games, data mining... The incremental notion of in band enrichment advanced at the ARTEMIS Department assumes that the enrichment data are directly inserted into the very original media to be enriched. In real life, in band enrichment can be supported by the watermarking technologies, assuming they afford a very large data payload, i.e. 10 to 1000 larger than the traditional copyright applications. The nowadays advent of the ubiquous media computing and storage applications imposes an additional constraint on the watermarking techniques: the enrichment data should be inserted into some compressed original media. A priori, such a requirement is a contradiction in terms, as compression eliminates the visual redundancy while the watermarking exploits the visual redundancy in order to imperceptibly insert the mark

Les fondements théoriques pour la saillance visuelle ont été dressés, il y a 35 ans, par Treisman qui a proposé "feature-integration theory" pour le système visuel humain: dans n’importe quel contenu visuel, certaines régions sont saillantes en raison de la différence entre leurs caractéristiques (intensité, couleur, texture, et mouvement) et leur voisinage. Notre thèse offre un cadre méthodologique et expérimental compréhensif pour extraire les régions saillantes directement des flux compressés (MPEG-4 AVC et HEVC), tout en minimisant les opérations de décodage. L’extraction de la saillance visuelle à partir du flux compressé est à priori une contradiction conceptuelle. D’une part, comme suggéré par Treisman, dans un contenu vidéo, la saillance est donnée par des singularités visuelles. D’autre part, afin d’éliminer la redondance visuelle, les flux compressés ne devraient plus préserver des singularités. La thèse souligne également l’avantage pratique de l’extraction de la saillance dans le domaine compressé. Dans ce cas, nous avons démontré que, intégrée dans une application de tatouage robuste de la vidéo compressée, la carte saillance agit comme un outil d’optimisation, ce qui permet d’augmenter la transparence (pour une quantité d’informations insérées et une robustesse contre les attaques prescrites) tout en diminuant la complexité globale du calcul. On peut conclure que la thèse démontre aussi bien méthodologiquement que expérimentalement que même si les normes MPEG-4 AVC et HEVC ne dépendent pas explicitement d’aucun principe de saillance visuelle, leurs flux préservent cette propriété remarquable reliant la représentation numérique de la vidéo au mécanisme psycho-cognitifs humains / The theoretical ground for visual saliency was established some 35 years ago by Treisman who advanced the integration theory for the human visual system: in any visual content, some regions are salient (appealing) because of the discrepancy between their features (intensity, color, texture, motion) and the features of their surrounding areas. This present thesis offers a comprehensive methodological and experimental framework for extracting the salient regions directly from video compressed streams (namely MPEG-4 AVC and HEVC), with minimal decoding operations. Note that saliency extraction from compressed domain is a priori a conceptual contradiction. On the one hand, as suggested by Treisman, saliency is given by visual singularities in the video content. On the other hand, in order to eliminate the visual redundancy, the compressed streams are no longer expected to feature singularities. The thesis also brings to light the practical benefit of the compressed domain saliency extraction. In this respect, the case of robust video watermarking is targeted and it is demonstrated that the saliency acts as an optimization tool, allowing the transparency to be increased (for prescribed quantity of inserted information and robustness against attacks) while decreasing the overall computational complexity. As an overall conclusion, the thesis methodologically and experimentally demonstrates that although the MPEG-4 AVC and the HEVC standards do not explicitly rely on any visual saliency principle, their stream syntax elements preserve this remarkable property linking the digital representation of the video to sophisticated psycho-cognitive mechanisms

The present thesis addresses the MPEG-4 AVC stream watermarking and considers two theoretical and applicative challenges, namely ownership protection and content integrity verification.From the theoretical point of view, the thesis main challenge is to develop a unitary watermarking framework (insertion/detection) able to serve the two above mentioned applications in the compressed domain. From the methodological point of view, the challenge is to instantiate this theoretical framework for serving the targeted applications. The thesis first main contribution consists in building the theoretical framework for the multi symbol watermarking based on quantization index modulation (m-QIM). The insertion rule is analytically designed by extending the binary QIM rule. The detection rule is optimized so as to ensure minimal probability of error under additive white Gaussian noise distributed attacks. It is thus demonstrated that the data payload can be increased by a factor of log2m, for prescribed transparency and additive Gaussian noise power. A data payload of 150 bits per minute, i.e. about 20 times larger than the limit imposed by the DCI standard, is obtained. The thesis second main theoretical contribution consists in specifying a preprocessing MPEG-4 AVC shaping operation which can eliminate the intra-frame drift effect. The drift represents the distortion spread in the compressed stream related to the MPEG encoding paradigm. In this respect, the drift distortion propagation problem in MPEG-4 AVC is algebraically expressed and the corresponding equations system is solved under drift-free constraints. The drift-free shaping results in gain in transparency of 2 dB in PSNR

In this thesis, we analyze the bandwidth requirements of MPEG-4 AVC video traffic and then propose and evaluate the accuracy of new MPEG-4 AVC video traffic models. First, we analyze the bandwidth requirements of the videos by comparing the statistical characteristics of the different frame types. We analyze their coefficient of variability, autocorrelation, and crosscorrelation in both short and long term. The Hurst parameter is also used to investigate the long range dependence of the video traces. We then provide an insight into B-frame dropping and its impact on the statistical characteristics of the video trace. This leads us to design two algorithms that predict the size of the B-frame and the size of the group of pictures (GOP) in the short-term. To evaluate the accuracy of the prediction, a model for the error is proposed. In a broadband cable network, B-frame size prediction can be employed by a cable headend to provision video bandwidth efficiently or more importantly, reduce bit rate variability and bandwidth requirements via selective B-frame dropping, thereby minimizing buffering requirements and packet losses at the set top box. It will be shown that the model provides highly accurate prediction, in particular for movies encoded in high quality resolution. The GOP size prediction can be used to provision bandwidth. We then enhance the B-frame and GOP size prediction models using a new scene change detector metric. Finally, we design an algorithm that predicts the size of different frame types in the long-term. Clearly, a long-term prediction algorithm may suffer degraded prediction accuracy and the higher complexity may result in higher latency. However, this is offset by the additional time available for long-term prediction and the need to forecast bandwidth usage well ahead of time in order to minimize packet losses during periods of peak bandwidth demands. We also analyze the impact of the video quality and the video standard on the accuracy of the model.

<p>This dissertation considers packet-switched wireless networks for transmission of variable-rate layered hybrid video streams. Target applications are video streaming and broadcasting services. The work can be divided into two main parts.</p><p>In the first part, a novel quality-scalable scheme based on coefficient refinement and encoder quality constraints is developed as a possible extension to the video coding standard H.264. After a technical introduction to the coding tools of H.264 with the main focus on error resilience features, various quality scalability schemes in previous research are reviewed. Based on this discussion, an encoder decoder framework is designed for an arbitrary number of quality layers, hereby also enabling region-of-interest coding. After that, the performance of the new system is exhaustively tested, showing that the bit rate increase typically encountered with scalable hybrid coding schemes is, for certain coding parameters, only small to moderate. The double- and triple-layer constellations of the framework are shown to perform superior to other systems.</p><p>The second part considers layered code streams as generated by the scheme of the first part. Various error propagation issues in hybrid streams are discussed, which leads to the definition of a decoder quality constraint and a segmentation of the code stream to transmit. A packetization scheme based on successive source rate consumption is drafted, followed by the formulation of the channel code rate optimization problem for an optimum assignment of available codes to the channel packets. Proper MSE-based error metrics are derived, incorporating the properties of the source signal, a terminate-on-error decoding strategy, error concealment, inter-packet dependencies, and the channel conditions. The Viterbi algorithm is presented as a low-complexity solution to the optimization problem, showing a great adaptivity of the joint source channel coding scheme to the channel conditions. An almost constant image qualiity is achieved, also in mismatch situations, while the overall channel code rate decreases only as little as necessary as the channel quality deteriorates. It is further shown that the variance of code distributions is only small, and that the codes are assigned irregularly to all channel packets.</p><p>A double-layer constellation of the framework clearly outperforms other schemes with a substantial margin. </p><p>Keywords — Digital lossy video compression, visual communication, variable bit rate (VBR), SNR scalability, layered image processing, quality layer, hybrid code stream, predictive coding, progressive bit stream, joint source channel coding, fidelity constraint, channel error robustness, resilience, concealment, packet-switched, mobile and wireless ATM, noisy transmission, packet loss, binary symmetric channel, streaming, broadcasting, satellite and radio links, H.264, MPEG-4 AVC, Viterbi, trellis, unequal error protection</p>

This dissertation considers packet-switched wireless networks for transmission of variable-rate layered hybrid video streams. Target applications are video streaming and broadcasting services. The work can be divided into two main parts. In the first part, a novel quality-scalable scheme based on coefficient refinement and encoder quality constraints is developed as a possible extension to the video coding standard H.264. After a technical introduction to the coding tools of H.264 with the main focus on error resilience features, various quality scalability schemes in previous research are reviewed. Based on this discussion, an encoder decoder framework is designed for an arbitrary number of quality layers, hereby also enabling region-of-interest coding. After that, the performance of the new system is exhaustively tested, showing that the bit rate increase typically encountered with scalable hybrid coding schemes is, for certain coding parameters, only small to moderate. The double- and triple-layer constellations of the framework are shown to perform superior to other systems. The second part considers layered code streams as generated by the scheme of the first part. Various error propagation issues in hybrid streams are discussed, which leads to the definition of a decoder quality constraint and a segmentation of the code stream to transmit. A packetization scheme based on successive source rate consumption is drafted, followed by the formulation of the channel code rate optimization problem for an optimum assignment of available codes to the channel packets. Proper MSE-based error metrics are derived, incorporating the properties of the source signal, a terminate-on-error decoding strategy, error concealment, inter-packet dependencies, and the channel conditions. The Viterbi algorithm is presented as a low-complexity solution to the optimization problem, showing a great adaptivity of the joint source channel coding scheme to the channel conditions. An almost constant image qualiity is achieved, also in mismatch situations, while the overall channel code rate decreases only as little as necessary as the channel quality deteriorates. It is further shown that the variance of code distributions is only small, and that the codes are assigned irregularly to all channel packets. A double-layer constellation of the framework clearly outperforms other schemes with a substantial margin. Keywords — Digital lossy video compression, visual communication, variable bit rate (VBR), SNR scalability, layered image processing, quality layer, hybrid code stream, predictive coding, progressive bit stream, joint source channel coding, fidelity constraint, channel error robustness, resilience, concealment, packet-switched, mobile and wireless ATM, noisy transmission, packet loss, binary symmetric channel, streaming, broadcasting, satellite and radio links, H.264, MPEG-4 AVC, Viterbi, trellis, unequal error protection