Abstract: A video coding method applied to an input signal consisting of a sequence of frames represented by one luminance matrix and two chrominance matrices generates a coded bitstream in which each data item is described by a bitstream syntax allowing any decoder to recognize and decode all the segments of the content of the bitstream. The syntax includes a flag provided for indicating at a high level description the presence, or absence, of chrominance components in the coded bitstream, and therefore allowing to deliver, at the decoding side, the information according to which chrominance descriptive elements have to be decoded, or not.

Abstract: The present invention relates to a video decoder (DEC) for decoding a bit stream (BS) corresponding to pictures (P) of a video signal, the coded pictures being likely to include macroblocks coded in a progressive and in an interlaced way. This decoder comprises a decoding unit (DEU) for decoding macroblocks coded in a progressive way and, according to the invention, a multiple instance unit (MIU) for presenting, for each field-predicted macroblock, a motion compensation vector associated with each field, constructing as many predicted entire macroblocks as fields with each corresponding motion compensation vector, and reconstructing said field-predicted macroblock by re-interlacing fields respectively taken from each corresponding predicted entire macroblock.

Abstract: The invention relates to a video coding method applied to a sequence of video frames and generating a coded bitstream constituted of video data that represent all the video object planes and are described in terms of separate channels. In said video data, each data item is described by means of a bitstream syntax allowing any decoder to recognize and decode all the segments of the content of said bitstream. The temporal resolution of the sequence is described by means of some specific syntactic elements. According to the invention, which finds an application for instance within the video compression standards of the MPEG family, the syntax also comprises specific flags for describing, in the coded bitstream, the maximum frame rate of each described channel.

Abstract: A method of concealing error within a surface delimited by edges and containing points with which erroneous values are associated. A new value is interpolated for at least one point on the surface from interpolation points defined in a projection step by the projections in orthogonal directions of the point to be interpolated onto the edges of the surface. Primary distances are determined between the point to be interpolated and the interpolation points. The sums of the primary distances in each of the directions are calculated, the sums being called secondary distances. The interpolation step provides for determination of the new value of a point to be interpolated from the values associated with the respective interpolation points weighted by weights calculated according to the respective primary distances and second distances.

Abstract: The invention relates to a method of coding a digital image comprising macroblocks in a binary data stream, comprising an estimation step, for macroblocks, of a capacity to be reconstructed by an error concealment method, a decision step for excluding macroblocks from the coding, a decision to exclude a macroblock from coding being made on the basis of the capacity of such macroblock to be reconstructed and a step of inserting a resynchronization marker into the binary data stream following the exclusion of one or more macroblocks.

Abstract: The invention relates to a method of concealing error within a surface delimited by edges and containing points IP with which erroneous values V[IP] are associated, comprising a step of interpolating INT a new value V′[IP] for at least one point IP on the surface from interpolation points TP, RP, BP, LP defined in a projection step PRO by the projections in orthogonal directions of the point to be interpolated IP onto the edges of the surface, a step PDC of determining primary distances TD, RD, BD, LD defined between the point to be interpolated IP and the interpolation points TP, RP, BP, LP, a step SDC of calculating the sums of the primary distances in each of the directions, said sums being called secondary distances VS, HS.

Abstract: The invention relates to a method of concealing errors in an image signal 101 transmitted in a macroblock compressed form. The method comprises a decoding step 102, a step 103 of detecting an erroneous macroblock, a classifying step and a correcting step 109 of correcting the erroneous macroblock in accordance with its class. The invention provides a cost effective classifying step. To this end, the classifying step consists of computing a gradient, in step 104, for each valid surrounding macroblock, for each pixel of a line or a column adjacent to the erroneous macroblock, evaluating the number of direction changes Cdir of the gradient in step 107, comparing the gradients with a first and a second threshold in steps 105 and 106, and classifying the erroneous macroblock in step 108 in accordance with the results of steps 104 to 107. The present invention is particularly relevant for correcting MPEG-compressed video signals, especially in systems where resource problems occur, for example, in mobile phones.

Abstract: The invention relates to a method of preprocessing data that correspond to arbitrarily shaped objects and comprise for each object a texture part and an object mask, said method comprising, for each object plane associated to an object, the steps of: (1) partitioning the object plane into bidimensional blocks; (2) introducing in each block a set of basis vectors chosen in order to express an estimate of the original pixel values as a linear combination of said basis vectors; (3) defining a cost function &psgr; to measure the distortion between the original expression of the pixel values and said estimate of this original expression; (4) finding the coefficients allowing to minimize said cost function &psgr;, said finding step itself comprising the following operations: initialization, extraction of the basis vectors restricted to the opaque pixels and calculation of projection coefficients, iterations, and interruption of said iterations according to a predetermined criterion.

Abstract: The invention relates to a video coding method applied to a sequence of frames and generating a coded bitstream in which each data item is described by means of a bitstream syntax allowing any decoder to recognize and decode all the segments of the content of said bitstream. According to the invention, which finds an application for instance within the video compression standards of the MPEG and ITU-H.26X families, the syntax comprises a flag provided for indicating at a high description level, for each channel described in the coded bitstream, the presence, or not, of an encoded residual signal, said residual being defined by means of a prediction technique, applied to previously decoded frames and followed by the construction of said residual signal.

Abstract: The invention relates to a video coding method applied to a sequence of video frames and generating a coded bitstream constituted of video data that represent all the video object planes and are described in terms of separate channels. In said video data, each data item is described by means of a bitstream syntax allowing any decoder to recognize and decode all the segments of the content of said bitstream. The temporal resolution of the sequence is described by means of some specific syntactic elements. According to the invention, which finds an application for instance within the video compression standards of the MPEG family, the syntax also comprises specific flags for describing, in the coded bitstream, the maximum frame rate of each described channel.

Abstract: The invention relates to a video coding method applied to an input signal IS consisting of a sequence of frames represented by one luminance matrix and two chrominance matrices. This method generates a coded bitstream CB in which each data item is described by means of a bitstream syntax allowing any decoder to recognize and decode all the segments of the content of said bitstream. According to the invention, which finds an application for instance within the video compression standards of the MPEG and ITU-H.26X families, the syntax comprises a flag provided for indicating at a high level description the presence, or not, of chrominance components in said coded bitstream, and therefore allowing to deliver, at the decoding side, the information according to which chrominance descriptive elements have to be decoded, or not.

Abstract: The invention relates to a method of coding a digital image comprising macroblocks in a binary data stream, comprising an estimation step, for macroblocks, of a capacity to be reconstructed by an error concealment method, a decision step for excluding macroblocks from the coding, a decision to exclude a macroblock from coding being made on the basis of the capacity of such macroblock to be reconstructed and a step of inserting a resynchronization marker into the binary data stream following the exclusion of one or more macroblocks.

Abstract: The invention relates to a method of preprocessing data that correspond to arbitrarily shaped objects and comprise for each object a texture part and an object mask, said method comprising, for each object plane associated to an object, the steps of: