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Browsing by Author "Silva, Vitor M. M. da"

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  • Drift-free multiple description intra video coding
    Publication . Correia, Pedro D. F.; Assunção, Pedro; Silva, Vitor M. M. da
    This paper proposes a multiple description coding scheme based on a multi-loop structure, which prevents drift distortion accumulation in intra predicted slices. The drift is compensated by generating a controlled amount of side information used by the decoder whenever any description is lost in the corresponding network path. The experimental results show that intra predicted slices do not suffer from drift and their quality is significantly improved (e.g., 6-8 dB) at reduced redundancy cost, (e.g., 0.2-0.25), in comparison with the open loop implementation. Error propagation in subsequent frames is also evaluated when one description is lost for a whole frame and for two rows of macroblocks. In both cases the overall video quality is significantly improved and considering normal GOP sizes the redundancy introduced by the proposed scheme is negligible.
    2009Conference paper Open access Show more
  • Intra-prediction for color image coding using YUV correlation
    Publication . Lucas, Luís F.R.; Rodrigues, Nuno M. M.; Faria, Sérgio M. M. de; Silva, Eduardo A. B. da; Carvalho, Murilo B. de; Silva, Vitor M. M. da
    In this paper we present a new algorithm for chroma prediction in YUV images, based on inter component correlation. Despite the YUV color space transformation for inter component decorrelation, some dependency still exists between the Y, U and V chroma components. This dependency has been previously used to predict the chrominance data from the reconstructed luminance. In this paper we show that a chrominance component can be more efficiently predicted by using the reconstructed data from both the luminance and the remaining chrominance signal. The proposed chroma prediction is implemented and tested using the Multidimensional Multiscale Parser (MMP) image encoding algorithm. It is shown that the new color prediction mode outperforms the originally proposed prediction methods. Furthermore, by using the new color prediction scheme, MMP is consistently better than the state-of-the-art H.264/AVC for coding both for the luminance and the chrominance image components.
    2010-09Conference paper Open access Show more