KEYWORDS: Video, Linear filtering, Chemical species, Associative arrays, Video compression, Motion estimation, Semantic video, Video coding, Computer programming, Rutherfordium
Achieving very low bitrates for video applications in a mobile environment is essential. Video codecs standards evolution had a tremendous impact in the development of digital video, making possible today widespread usage of video data. At the same time it had an impact on the direction of research, biasing most of the efforts towards block based video. Alternative approaches may though lead towards different architectures able to provide higher compression efficiency. In this paper we propose a Matching Pursuit (MP) based video coder that adopts a generalized sub-pixel motion compensation and arithmetic coding. We introduce a new dictionary, and an adaptive grid for atom coding combined with an arithmetic coder. Comparison with H.264 show an improvement of up to 20% in compression efficiency for the same PSNR
KEYWORDS: Image processing, Multimedia, Computer programming, Digital signal processing, Signal processing, Video processing, Video, Video coding, Motion estimation, Data processing
This paper proposes a classification of the parallelisms in general-purpose processor based systems in three main categories. One category is the intra-processor parallelism that includes multimedia instructions and superscalar and VLIW architectures. The former takes advantage of data parallelism. The latter benefit from instruction level parallelism. Another category is the inter-processor parallelism. We consider the parallelism between processors inside shared memory symmetric multiprocessor systems and in distributed memory clusters of workstations. Finally, in the last category, main features of the system level parallelism are studied including the input/output operations, the memory hierarchy and the exploitation of external processing. The potential gain is studied for each type of parallelism available in general-purpose processor based systems from a theoretical point of view as well as for existing image and video applications. The results in this paper showed that the exploitation of the different levels of parallelism available in PC workstations can lead to considerable gains in speed when optimizing a multimedia application. Finally the results of this work can be used to influence the design of new multimedia systems and media processors.
Motion estimation represents the main computational burden of every hybrid video encoder. Various solutions have been proposed in order to reduce the number of operations needed for this task, trying to keep good quality of the estimation and of the relative encoded video. In this paper we propose an algorithm that, exploiting the statistical properties of the motion field, searches a number of points dynamically related to the evolution of the sequence. A subsampling pattern of the macroblock is also proposed to reduce the overall impact of the motion estimation in an MPEG encoder.
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