Abstract: A method of transmitting an image portion, in a coding phase, comprises: analyzing a coding context; adapting a parameter of a group of prediction functions that can be used for coding; forming a first predicted descriptor using a selected prediction function; and determining and transmitting a residue (?) between the first predicted descriptor and the current descriptor. The method further includes a decoding phase comprising: analyzing a decoding context; adapting a parameter of a group of prediction functions that can be used for decoding; forming a second predicted descriptor (P*) using a selected prediction function; and combining the second predicted descriptor and the received residue to deliver a decoded version of the current descriptor (V*).

Abstract: A method is provided for decoding a signal that represents at least one image. The method implements at least one iteration of the following steps, for at least one block of the image to be decoded: determining at least one selection parameter from at least one characteristic associated with at least one reference pixel of a reference region of the image, the reference region including at least one previously encoded/decoded block and/or at least one pixel predicted in a preceding iteration; selecting at least one pixel to be predicted in the block to be decoded from the at least one selection parameter; and for at least one selected pixel to be predicted, referred to as an anchor pixel, predicting the anchor pixel from at least one reference pixel, thereby outputting a predicted pixel.

Abstract: A method for broadcasting images from a video sequence, the method comprising, at the level of broadcasting equipment: including images in an output stream for transmission to at least one restoration equipment, receiving feedback from said restoration equipment of error messages relating to the restoration of the images from the video sequence, analyzing the error messages in order to identify images or parts of images not restored or badly restored and determining response messages including correction images or image parts. The method furthermore comprising determining a level of seriousness for each error message according to the analysis performed and deciding to return a response message relating to an error message according to the level of seriousness of that error message.

Abstract: A video coding method, comprising the following steps: a) successive images (F) of a video sequence are coded to generate coding parameters, b) the coding parameters are included in an output stream (?) to be transmitted to a station (B) including a decoder (2), c) back channel information on reconstruction of the images of the video sequence by the decoder is received from said station, d) the back channel information is analyzed in order: d1) to identify a reconstructed image that includes a portion that has been lost in the decoder, d2) to identify in the subsequent coded images between said reconstructed image and a current image to be coded an image portion that refers to said lost portion identified in the step d1), e) said current image of the video sequence is coded in a coding mode that is a function of the identification or non-identification of a lost portion in the step d).

Abstract: A method and apparatus are provided for processing movement information relating to a regular image of a sequence of images. The method includes: a step of building a list including at least one expected piece of movement information and at least one unexpected piece of movement information; a first step of associating expected movement information with movement information according to a first rule for optimizing the cost of encoding the movement information to be encoded; a second step of associating each unexpected piece of movement information not associated during the first association step with movement information to be encoded, identified among the pieces of movement information of the list, according to a second rule which aims to ensure that each piece of movement information is associated with a single piece of movement information to be encoded.

Abstract: A method is provided for encoding an image or a sequence of images generating a data flow comprising data representing a group of pixels in one of said images, said method including: calculating a predetermined number of predictors in relation to said group of pixels, and selecting an optimal predictor in accordance with a predetermined selection criterion. Between the calculation and selection steps, a step of eliminating at least one predictor with a calculated predetermined number is performed, which comprises, for at least two ith (Pi) and jth (Pj) predictors, of: calculating the difference between said jth and ith predictors, applying a transform to said calculated difference, performing a quantification operation on the result of the applied transform, comparing the result of said quantification operation with a predetermined value, eliminating the jth predictor if the result of said quantification operation is less than or equal to said predetermined value.

Abstract: A method and device relate to coding an image split up into partitions, which comprises the selection of at least one mode of coding and of its associated coding information items, from among items placed in competition, the prediction of the data of a current partition, the determination of residual data. Calculation of the value of a function representative of said residual data are performed, then the comparison of said calculated value with a value selected as value of competition index from among the associated values. If the values are equal, said signal transmitted comprises said residual data and said associated coding information items. If not, the residual data determined are modified so that the value of the function representative of the residual data is equal to the selected value of competition index, the signal transmitted comprising the modified residual data, excluding the selected value of competition index.

Abstract: A method is provided for encoding an image signal that includes motion information, by selecting a motion vector from among a set of at least three candidate vectors for at least one actual block of an actual image to be encoded. The method includes: determining an optimal-selection subset containing some of the candidate vectors; selecting the motion vector from among the vectors of the optimal-selection subset; and inserting into the signal a piece of information designating the motion vector selected from among the vectors of the optimal-selection subset.

Abstract: A method and apparatus are provided for predicting a movement vector of a current image partition in relation to a movement vector of a reference partition having the same form as the current image partition and belonging to a reference image (IN-1) which is different from the current image and has been pre-cut, following encoding and subsequent decoding, into a plurality of n partitions. One such method includes, when the reference partition covers a set of k reference partitions from among the plurality of n reference image partitions, with k?n, determining the movement vector of the current image partition from a function of at least one reference movement vector belonging to a set of k reference movement vectors associated respectively with k covered reference partitions.

Abstract: The invention relates to a method for predicting a movement vector (MVp1) of a partition (P1) of a current image (IN) from a plurality of n reference movement vectors associated respectively with n reference partitions that have been previously encoded and decoded. For a spatial prediction of one such vector, when the geometric shape of the current partition is different from that of k adjacent reference partitions (pr1, pr2, . . . prk), with k?n, the movement vector of the current image partition is determined from a function of at least one reference movement vector belonging to a set of k reference movement vectors associated respectively with k adjacent reference partitions.

Abstract: A method is provided for decoding a data stream representative of an image or of a sequence of images, the stream comprising data representative of at least one portion of one of the images, the method implementing a step of predicting a motion vector of a partition of a current image portion, with respect to a reference causal zone which has been partitioned according to a mode of coding determined for the zone. The prediction step comprises, in relation to said current partition: partitioning anew at least one portion of the reference causal zone into a plurality of reference partitions, determining motion vectors respectively associated with reference partitions obtained subsequent to the new partitioning, determining a predictor motion vector on the basis of said determined motion vectors, and predicting the motion vector of said current partition on the basis of said determined predictor motion vector.

Abstract: A method is provided for encoding an image or a sequence of images generating a data flow comprising data representing a group of pixels in one of said images, said method including: calculating a predetermined number of predictors in relation to said group of pixels, and selecting an optimal predictor in accordance with a predetermined selection criterion. Between the calculation and selection steps, a step of eliminating at least one predictor with a calculated predetermined number is performed, which comprises, for at least two ith (Pi) and jth (Pj) predictors, of: calculating the difference between said jth and ith predictors, applying a transform to said calculated difference, performing a quantification operation on the result of the applied transform, comparing the result of said quantification operation with a predetermined value, eliminating the jth predictor if the result of said quantification operation is less than or equal to said predetermined value.

Abstract: The present invention relates to a method of encoding a sequence of pictures, a picture being divided into blocks of data, said encoding method comprising the steps of:—computing a residual error block from a difference between a current block contained in a current picture and a candidate area using of a prediction function,—computing an entropy of the residual error block,—computing an overall error between said current block and said candidate area,—estimating a power consumption of a video processing device adapted to implement said prediction function,—computing a rate-distortion value on the basis of the entropy, the overall error and the estimated power consumption of the video processing device,—applying the preceding steps to a set of candidate areas using a set of prediction functions in order to select a prediction function according to the rate-distortion value.

Abstract: A method is provided for predicting partitions of at least one group of pixels in an image to be coded, with respect to a group of reference pixels. Accordingly, the group of reference pixels is obtained by calculating a function characteristic of a predetermined mode of prediction, the reference pixels of the group obtained being variable from one partition to another.

Abstract: A method is provided of coding an image or a sequence of images generating a stream of data comprising data representative of at least one group of pixels in one of said images. Such a method comprises the steps of: selecting, for a group of pixels to be coded, an initial partition of predetermined linear form, slicing said group of pixels to be coded according to said selected initial partition, propagating said initial partition selected in said group of pixels to be coded, until the latter is sliced in its entirety into a plurality of partitions of predetermined form, selecting, for said sliced group of pixels, a predetermined order of traversal of said partitions, predicting and coding said partitions one after the other, according to said selected order of traversal.

Abstract: The present invention relates to method of coding blocks of video data for a handheld apparatus comprising a battery. Said method comprising a step of computing a residual error block from the use of a set of prediction functions having different power consumption levels. It also comprises a step of enabling or disabling a prediction function of the set depending on its associated power consumption level for a predetermined level of the battery. It finally comprises a step of selecting a prediction function among a set of enabled prediction functions to code the residual error block.

Abstract: A method is provided for encoding a portion of a current image, including: an estimation of motion between the current image portion and a plurality of candidate image portions in order to form motion components, an evaluation of a performance criterion for each candidate image portion, and the selection of a reference image portion using said performance criteria. In the method, for at least one motion component, the motion estimation, the performance criteria evaluation and the reference image portion selection only use information considered to be available at the decoder and no motion information is inserted into an output flow intended for a decoder. A corresponding decoding method is also provided.

Abstract: The present invention relates to a method of transmitting at least one current image portion, wherein the method comprises selecting a coding function from a finite set of coding functions by applying at least one choice function of a first type, said choice function or functions of said first type using already-decoded image data, coding the current image portion using the selected coding function, sending the coded image portion to a decoder, and sending to said decoder information describing the choice function or functions of said first type. The invention also relates to the corresponding decoding method.

Abstract: A video coding method, comprising the following steps: a) successive images (F) of a video sequence are coded to generate coding parameters, b) the coding parameters are included in an output stream (?) to be transmitted to a station (B) including a decoder (2), c) back channel information on reconstruction of the images of the video sequence by the decoder is received from said station, d) the back channel information is analyzed in order: d1) to identify a reconstructed image that includes a portion that has been lost in the decoder, d2) to identify in the subsequent coded images between said reconstructed image and a current image to be coded an image portion that refers to said lost portion identified in the step d1), e) said current image of the video sequence is coded in a coding mode that is a function of the identification or non-identification of a lost portion in the step d).

Abstract: The invention relates to a method for broadcasting images from a video sequence, the method comprising the following steps at the level of a broadcasting equipment (2): including images (14) in an output stream for transmission to at least one restoration equipment; receiving in return from said restoration equipment error messages relating to the restoration of images from the video sequence; analysing (24) the error messages in order to identify images or images parts which are not or restored badly restored; determining (32) answer messages including correction images or image parts. The method is characterised in that it further comprises: a step (26) for determining a level of seriousness (FGi) for each error message according to the analysis performed; and a decision step (30) for sending back a response message to an error message according to the level of seriousness of the error message.