Current Issue : July - September Volume : 2012 Issue Number : 3 Articles : 4 Articles
A novel watermarking framework for scalable coded video that improves the robustness against quality scalable compression is\r\npresented in this paper. Unlike the conventional spatial-domain (t + 2D) water-marking scheme where the motion compensated\r\ntemporal filtering (MCTF) is performed on the spatial frame-wise video data to decompose the video, the proposed framework\r\napplies the MCTF in the wavelet domain (2D + t) to generate the coefficients to embed the watermark. Robustness performances\r\nagainst scalable content adaptation, such asMotion JPEG 2000, MC-EZBC, or H.264-SVC, are reviewed for various combinations\r\nof motion compensated 2D+t+2D using the proposed framework. The MCTF is improved by modifying the update step to\r\nfollow the motion trajectory in the hierarchical temporal decomposition by using direct motion vector fields in the update step and\r\nimplied motion vectors in the prediction step. The results show smaller embedding distortion in terms of both peak signal to noise\r\nratio and flickering metrics compared to frame-by-frame video watermarking while the robustness against scalable compression is\r\nimproved by using 2D + t over the conventional t + 2D domain video watermarking, particularly for blind watermarking schemes\r\nwhere the motion is estimated from the watermarked video....
Interoperability explains how two or more systems or components exchange and process information. The heterogeneity\r\ncommunication mechanisms of the components (GPRS, WIFI, Bluetooth, ZigBee, etc.), transmission speed, as well as the variety\r\nof the media (sound, video, text, and image) they manage have a strong influence on the interoperability. That requires the\r\nmanagement of the adaptation to an abstract level in order to avoid ad hoc nonreusable, and/or generalizable solutions. In this\r\npaper we propose a metamodel for architectures with heterogeneous multimedia components. It enables the description of the\r\nsoftware architectures as a collection of components manipulating various types and formats of data, and interacting between\r\nthem via specific adaptation connectors....
First unequal error protection (UEP) proposals date back to the 1960�s (Masnick and Wolf; 1967), but now with the introduction\r\nof scalable video, UEP develops to a key concept for the transport of multimedia data. The paper presents an overview of some\r\nnew approaches realizing UEP properties in physical transport, especially multicarrier modulation, or with LDPC and Turbo\r\ncodes. For multicarrier modulation, UEP bit-loading together with hierarchical modulation is described allowing for an arbitrary\r\nnumber of classes, arbitrary SNR margins between the classes, and arbitrary number of bits per class. In Turbo coding, pruning,\r\nas a counterpart of puncturing is presented for flexible bit-rate adaptations, including tables with optimized pruning patterns. Bitand/\r\nor check-irregular LDPC codes may be designed to provide UEP to its code bits. However, irregular degree distributions alone\r\ndo not ensure UEP, and other necessary properties of the parity-check matrix for providing UEP are also pointed out. Pruning is\r\nalso the means for constructing variable-rate LDPC codes for UEP, especially controlling the check-node profile....
This paper describes an approach to exploit the implicit user feedback gathered during interactive video retrieval tasks. We\r\npropose a framework, where the video is first indexed according to temporal, textual, and visual features and then implicit user\r\nfeedback analysis is realized using a graph-based methodology. The generated graph encodes the semantic relations between\r\nvideo segments based on past user interaction and is subsequently used to generate recommendations. Moreover, we combine\r\nthe visual features and implicit feedback information by training a support vector machine classifier with examples generated\r\nfrom the aforementioned graph in order to optimize the query by visual example search. The proposed framework is evaluated\r\nby conducting real-user experiments. The results demonstrate that significant improvement in terms of precision and recall is\r\nreported after the exploitation of implicit user feedback, while an improved ranking is presented in most of the evaluated queries\r\nby visual example....
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