Dolby International Ab

Orange

Canon Kabushiki Kaisha

B-com

Canon Europa N.v.

Fondation B Com

Canon Research Centre France

Felix Henry

Gordon Clare

Stephane Pateux

Joel Jung

Mohsen Abdoli

Bappaditya Ray

Charlene Mouton

Patrice Onno

Jean-Jacques Moreau

Stéphane Pateux

Eric Majani

Bertrand Berthelot

Patrice Houze

Maryline Charrier

Claude Dierieck

Bihong Huang

Clare Gordon

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.

Method of coding and decoding images, coding and decoding device and computer programs corresponding thereto

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.

A method for encoding an image having been cut up into partitions. The method includes: predicting data of a current partition based on an already encoded and then decoded reference partition, generating a predicted partition; determining residual data by comparing data relating to the current partition with the predicted partition, the residual data associated with various digital data items. Prior producing a signal containing the encoded information, performing the following steps; determining, from the predetermined residual data, a subset containing residual data capable of being modified; calculating the value of a function representative of the residual data; comparing the calculated value with a value of at least one of the digital data items; based on the comparison, modification or non-modification of at least one of the residual data items of the subset; and, in the event of a modification, entropy encoding the at least one modified residual data item.

A method is provided for coding at least one image split up into partitions, a current partition to be coded containing data, at least one data item of which is allotted a sign. The coding method includes, for the current partition, the following steps: calculating the value of a function representative of the data of the current partition with the exclusion of the sign; comparing the calculated value with a predetermined value of the sign; as a function of the result of the comparison, modifying or not modifying at least one of the data items of the current partition, in the case of modification, coding the at least one modified data item.

A coding method and a decoding method for decoding a coded data stream representative of at least one image that is split into blocks. For at least one current block of the image, an item of information indicating a coding mode of the current block is decoded from the data stream. When the coding mode of the current block corresponds to a first coding mode, the current block is decoded using a first determined quantization step to dequantize, in the transform domain, a prediction residue associated with the current block. When the coding mode of the current block corresponds to a second coding mode, the current block is decoded using a second determined quantization step to dequantize, in the spatial domain, a prediction residue associated with the current block. The first quantization step and the second quantization step are determined according to the same quantization parameter.

Methods and devices for coding and decoding a data stream representative of at least one image

A method for encoding at least one image, including subdividing the image into a plurality of blocks and subdividing at least one current block into a first portion and a second portion. The first portion has a rectangular or square shape and the second portion complements the first portion in the current block. The second portion has a geometric shape with m sides, wherein m&#x3e;4. Then the first and second portions are encoded.

Segmentation method and method for signaling segmentation of a coding tree unit

A method and device for encoding an image divided into blocks. The image contains two separate zones. The method implements the following: only in the event where the current block pertains to one of the zones of the image: encoding the current block using a prediction, the current block being predicted using a previously encoded and then decoded block located in the other zone of the image, the blocks of the other zone having been previously encoded and then decoded, and encoding information indicating the application of the prediction; and for any decoded block pertaining to the other zone of the image, storing the decoded block data.

Method for encoding and decoding images according to distinct zones, encoding and decoding device, and corresponding computer programs

A method and device for encoding and a method and device for decoding a signal including encoded data representing an image sub-divided into blocks, and information representing a correction block and a residual block. For a current block of the image, a first pixel is encoded from a prediction value obtained for the first pixel from at least one pixel of a previously rebuilt block. The prediction is corrected using at least one value of a pixel of the correction block. At least one current pixel of the current block is encoded from a prediction value obtained for the current pixel from at least one previously corrected pixel of the current block. The prediction is corrected by using at least one value of a pixel of the correction block, delivering a prediction block for the current block. The residual block is computed from the current block and the predictive block.

Coding and decoding methods for coding and decoding a coded data stream representing at least one image split into blocks. The method includes, for a current block, determining if the current block is coded according to an intra coding mode or another coding mode, the intra coding mode using an intra prediction mode selected from a group of intra prediction modes, according to an intra prediction mode associated with a neighbouring block of the current block. When coded according to the intra coding mode, an intra prediction mode in the group is determined for the current block, according to an intra prediction mode associated with a previously decoded block of the image. The current block is decoded according to the determined intra prediction mode associated with the current block. When coded according to the other coding mode, the current block is decoded according to the other coding mode.

A method for decoding an encoded data stream representative of at least one image, which is divided into blocks. The decoding method includes, for a current block: evaluating a plurality of value hypotheses of at least one description element of the current block, by calculating a likelihood measurement per hypothesis; calculating a disparity in the likelihood measurements obtained; determining at least one parameter of a decoder based on the calculated disparity; decoding, using the determined decoder, complementary information for identifying at least one of the hypotheses; and identifying at least one of the hypotheses using the decoded complementary information and obtaining a value of the at least one description element for the current block, from the at least one identified hypothesis.

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Saint Gregoire, France

Felix Henry