This paper studies quantization error in the context of Matching Pursuit coded streams. The quantization noise is shown to depend on error on both coefficients and indexes. It is moreover influenced by the redundancy of the Matching Pursuit dictionary. A novel general formulation of the structural redundancy in overcomplete decompositions is shown to enhance the accuracy of classical redundancy...

In this paper, we propose a RAID-disk placement algorithm of coded video data and an efficient disk prefetching method to increase the number of clients who can be serviced interactive operations in the media server. Our placement policy is incorporated with a special bit count control method that is based on repeated tuning of quantization parameters to adjust the actual bit count to the targe...

This letter presents a new approach to reduce coding artifacts in transform image coding. We approach the problem in an estimation of each transform coeecient from its quantized version with its local mean and variance. The proposed method can reduce much coding artifacts of low bit-rate coded images, and at the same time guarantee that the resulting images satisses the quantization error const...

19. ABSTRACT (Continue on reverse if necessary and identify by block number) Several block and convolutional coding options are considered which are applicable to the noncoherent detection of FH/MFSK signals in the presence of tone jamming. The tone jamming model used in this report is the worst-cast tone jamming for an uncoded system. Using decoded probability of bit error as a performance cri...

Entropy coded vector quantization is studied using high resolution multidimensional companding over a class of non-diierence distortion measures. For distortion measures which are \locally quadratic" a rigorous derivation of the asymptotic distortion and entropy coded rate of multidimensional companders is given along with conditions for the optimal choice of the compressor function. This optim...

Entropy-coded vector quantization is studied using high-resolution multidimensional companding over a class of nondifference distortion measures. For distortion measures which are “locally quadratic” a rigorous derivation of the asymptotic distortion and entropy-coded rate of multidimensional companders is given along with conditions for the optimal choice of the compressor function. This optim...

A video coding system is described which uses adaptive quantization of spatio-temporal subbands to enable transmission of near NTSC resolution color image sequences over a 1.5 megabit channel. The sequence is first decomposed into spatio-temporal spectral components using quadrature mirror filters. Simple heuristics are used to determine the local importance of a given component's energy. These...

In this paper, we evaluate the choice of suitable quantization characteristics for both the decoder messages and the received samples in Low Density Parity Check (LDPC) coded systems using M-QAM (Quadrature Amplitude Modulation) schemes. The analysis involves the demapper block that provides initial likelihood values for the decoder, by relating its quantization strategy of the decoder. A mappi...

When a bitstream of the higher bitrate is converted to the lower bitrate through the transcoding process, the ROI (Regions of Interest) can be considered. We classify the ROI as the groups of macro-blocks with non-zero motion vectors. For simple implementation, the motion vectors are not additionally estimated, but extracted from the coded bitstream of the higher bitrate before trascoding. Then...