Abstract:
A method of coding at least one image comprising the steps of splitting the image into a plurality of blocks, of grouping said blocks into a predetermined number of subsets of blocks, of coding each of said subsets of blocks in parallel, the blocks of a subset considered being coded according to a predetermined sequential order of traversal. The coding step comprises, for a current block of a subset considered, the sub-step of predictive coding of said current block with respect to at least one previously coded and decoded block, and the sub-step of entropy coding of said current block on the basis of at least one probability of appearance of a symbol.
Abstract:
A method of coding at least one image comprising the steps of splitting the image into a plurality of blocks, of grouping said blocks into a predetermined number of subsets of blocks, of coding each of said subsets of blocks in parallel, the blocks of a subset considered being coded according to a predetermined sequential order of traversal. The coding step comprises, for a current block of a subset considered, the sub-step of predictive coding of said current block with respect to at least one previously coded and decoded block, and the sub-step of entropy coding of said current block on the basis of at least one probability of appearance of a symbol.
Abstract:
A method for coding includes; segmenting an image into blocks; grouping blocks into a number of subsets; coding, using an entropy coding module, each subset, by associating digital information with symbols of each block of a subset, including, for the first block of the image, initializing state variables of the coding module; and generating a data sub-stream representative of at least one of the coded subsets of blocks. Where a current block is the first block to be coded of a subset, symbol occurrence probabilities for the first current block are determined based on those for a coded and decoded predetermined block of at least one other subset. Where the current block is the last coded block of the subset: writing, in the sub-stream representative of the subset, the entire the digital information associated with the symbols during coding of the blocks of the subset, and implementing the initializing sub-step.
Abstract:
A method of coding an image or a sequence of images generating a flow of data in the form of groups of blocks, at least one group of blocks containing image blocks having a resolution and a quality level of identical quantification, the method including the following steps for the at least one group of blocks, of a) a first coding so that each block of the at least one group of blocks has at least one associated parameter that is given a first value, and b) a second coding for giving the associated parameter for at least one block of the at least one group of blocks a second value, so that for the at least one block, the first and second values given for the parameter can be combined during decoding to provide a value assigned to the parameter.
Abstract:
A method is provided for filtering a scalable video stream, organized in the form of data unit blocks, each of which comprises a base data unit and a set of data units distributed according to two types of enhancement data, corresponding respectively to time and/or space and/or quality characteristics and making it possible to define several quality levels. The method defines at least two distinct filtering profiles, or paths of each block data units, wherein each path defines a row of successive foldover positions and each foldover position uses at least by one less data units than a previous position, and selects one of the paths according to a predetermined criterion, taking into account the type of content of the stream and/or at least one information item representing the capacities of a terminal receiving the stream.
Abstract:
A video image sequence is coded or decoded. By motion compensated temporal filtering, using discrete wavelet decomposition, the discrete wavelet is decomposed by dividing the video image sequence into source and destination groups of images. An image in the destination group is determined from at least one image including pixels in the first group of the source group. The representative image includes pixels and subpixels determined from pixels and subpixels obtained by upsampling at least one image in the source group.
Abstract:
A method is provided for filtering a scalable video stream, organized in the form of data unit blocks, each of which comprises a base data unit and a set of data units distributed according to two types of enhancement data, corresponding respectively to time and/or space and/or quality characteristics and making it possible to define several quality levels. The method defines at least two distinct filtering profiles, or paths of each block data units, wherein each path defines a row of successive foldover positions and each foldover position uses at least by one less data units than a previous position, and selects one of the paths according to a predetermined criterion, taking into account the type of content of the stream and/or at least one information item representing the capacities of a terminal receiving the stream.
Abstract:
A method is provided decoding a digital image signal in a decoding terminal that uses a variable-complexity decoding, enabling, for at least one step in the decoding, selection of at least one decoding tool from at least two available decoding tools. The method includes the following steps: identifying from the images control images and intermediate images; applying to each of the control images, for at least one step of the decoding, at least one predetermined decoding tool imposed by the signal; applying to at least one of the intermediate images, for at least one step of the decoding, at least one decoding tool selected by the decoding terminal and not imposed by the signal.
Abstract:
A method is provided for encoding a sequence of images generating a data stream in the form of a structure of embedded data layers of n successive levels each of which corresponds to the predetermined resolution of said images. Said method comprises an encoding stage, which encodes at least one of said layers of an n+1 level by prediction on the basis of said level n layer and encodes each data layer of the level n in the form of a base sub-stream and, optionally, in the form of at least one enhancement sub-stream enabling to obtain at least one version of the enhanced quality of said images. The method also encodes, for at least one data layer of the n level, at least one single sub-stream enabling to reconstruct the version of said images at said level n resolution with a quality higher than said enhanced qualities, wherein said single sub-steam of the level n layer is not used during the prediction encoding of the layers of a level other than the level n.
Abstract:
A method is provided for encoding an image represented by a sequence of symbols. The method includes the following steps: defining subsequences within the sequence; and going through the subsequences applying the following sub-steps for a routine subsequence: determining an adjacent routine encoded group including two previously encoded subsequences, one of which belongs to an adjacent encoded group associated with a subsequence that is separate from the routine subsequence; initializing a routine probability of occurrence of a symbol, taking into account two known probabilities of occurrence of the symbol, relating to two previously encoded subsequences of the adjacent routine encoded group; the consecutive entropic encoding of the symbols, and updating the routine probability of occurrence; and storing the routine probability of occurrence after encoding the last symbol.