Abstract: The invention relates to an encoding method for the compression of a video sequence by means of a tridimensional wavelet transform. This method is based on a hierarchical subband encoding process leading to transform coefficients constituting a hierarchical pyramid. A spatio-temporal orientation tree, in which the roots are formed with the pixels of the approximation subband and the offspring of each of these pixels is formed with the pixels of the higher subbands, defines the spatio-temporal relationship inside said pyramid. According to the invention, the initial subband structure of the wavelet transform is preserved, in the encoding process, by scanning the subbands one after the other in an order that respects the parent-offspring dependencies formed in the tree.

Abstract: The invention relates to an encoding method for the compression of a video sequence. Said method, using a three-dimensional wavelet transform, is based on a hierarchical subband coding process in which the subbands to be encoded are scanned in an order that preserves the initial subband structure of the 3D wavelet transform. According to the invention, a temporal (resp. spatial) scalability is obtained by performing a motion estimation at each temporal resolution level (resp. at the highest spatial resolution level), and only the part of the estimated motion vectors necessary to reconstruct any given temporal (resp. spatial) resolution level is then encoded and put in the bitstream together with the bits encoding the wavelet coefficients at this given temporal (resp. spatial) level, said insertion in the bitstream being done before encoding texture coefficients at the same temporal (resp. spatial) level.

Abstract: The invention relates to an encoding method for the compression of a video sequence including successive frames organized in groups of frames. Each frame is decomposed by means of a three-dimensional (3D) wavelet transform leading to a given number of successive resolution levels. This method is based on the SPIHT algorithm that transforms the original set of picture elements (pixels) of each group of frames into transform coefficients constituting a hierarchical pyramid in which a spatio-temporal orientation tree—in which the roots are formed with the pixels of the approximation subband resulting from the 3D wavelet transform and the offspring of each of these pixels is formed with the pixels of the higher subbands corresponding to the image volume defined by these root pixels—defines the spatio-temporal relationship.

Abstract: The invention relates to an encoding method for the compression of a video sequence divided in flames decomposed by means of a wavelet transform. Said method, based on the hierarchical subband encoding process called “set partitioning in hierarchical trees” (SPIHT), leads from the original set of picture elements of the video sequence to wavelet transform coefficients encoded with a binary format. These coefficients are organized in trees and ordered into partitioning sets respectively corresponding to levels of significance, by means of magnitude tests leading to a classification into three ordered lists called list of insignificant sets (LIS), list of insignificant pixels (LIP) and list of significant pixels (LSP). According to the invention, a specific initialization order of the LIS is proposed.

Abstract: The invention relates to an encoding method for the compression of a video sequence. Said method, using a three-dimensional wavelet transform, is based on a hierarchical subband coding process in which the subbands to be encoded are scanned in an order that preserves the initial subband structure of the 3D wavelet transform. According to the invention, a temporal (resp. spatial) scalability is obtained by performing a motion estimation at each temporal resolution level (resp. at the highest spatial resolution level), and only the part of the estimated motion vectors necessary to reconstruct any given temporal (resp. spatial) resolution level is then encoded and put in the bitstream together with the bits encoding the wavelet coefficients at this given temporal (resp. spatial) level, said insertion in the bitstream being done before encoding texture coefficients at the same temporal (resp. spatial) level.

Abstract: In order to compress a video sequence under the constraint of scability, the known 2D or 3D SPIHT, based on the prediction of the absence of significant information across scales of a wavelet decomposition, compares a set of pixels, corresponding to the same image area at different resolutions, to a value called level of significance. In both cases, the transform coefficients are ordered by means of magnitude tests involving the pixels represented by three ordered lists called list of insignificant sets (LIS), list of insignificant pixels (LIP) and list of significant pixels (LSP). In the original video sequence, the value of a pixel depends on those of the pixels surrounding it. The estimation of the probability of a symbol given the d previous bits becomes a difficult task when the number of conditioning events increases.

Abstract: The invention relates to an encoding method for the compression of a video sequence by means of a tridimensional wavelet transform. This method is based on a hierarchical subband encoding process leading to transform coefficients constituting a hierarchical pyramid. A spatio-temporal orientation tree, in which the roots are formed with the pixels of the approximation subband and the offspring of each of these pixels is formed with the pixels of the higher subbands, defines the spatio-temporal relationship inside said pyramid. According to the invention, the initial subband structure of the wavelet transform is preserved, in the encoding process, by scanning the subbands one after the other in an order that respects the parent-offspring dependencies formed in the tree.

Abstract: The invention relates to an encoding method for the compression of a video sequence including successive frames organized in groups of frames. Each frame is decomposed by means of a three-dimensional (3D) wavelet transform leading to a given number of successive resolution levels. This method is based on the SPIHT algorithm that transforms the original set of picture elements (pixels) of each group of frames into transform coefficients constituting a hierarchical pyramid in which a spatio-temporal orientation tree—in which the roots are formed with the pixels of the approximation subband resulting from the 3D wavelet transform and the offspring of each of these pixels is formed with the pixels of the higher subbands corresponding to the image volume defined by these root pixels—defines the spatio-temporal relationship.

Abstract: The invention relates to an encoding method for the compression of a video sequence divided in flames decomposed by means of a wavelet transform. Said method, based on the hierarchical subband encoding process called “set partitioning in hierarchical trees” (SPIHT), leads from the original set of picture elements of the video sequence to wavelet transform coefficients encoded with a binary format. These coefficients are organized in trees and ordered into partitioning sets respectively corresponding to levels of significance, by means of magnitude tests leading to a classification into three ordered lists called list of insignificant sets (LIS), list of insignificant pixels (LIP) and list of significant pixels (LSP). According to the invention, a specific initialization order of the LIS is proposed.