Abstract: An aspect of present principles is directed to methods and systems for gamut mapping colors from a either a source color gamut or a content color gamut towards a target color gamut. A source hue of the source specific colors and a source hue of the content specific colors is changed towards a target hue of the corresponding target specific colors. Color gamut mapping is performed for the source colors of either the whole source color gamut or the content color gamut towards the target color gamut based on the mapped specific colors. The specific colors are selected from primary colors, secondary colors, a group of primary colors and secondary colors.

Abstract: This determination comprises: defining key constant-hue leaves such as to partition the gamut mapping color space into angular hue sectors; for each key constant hue leaf, defining a key hue leaf chroma mapping function; for each angular hue sector, defining a continuous angular hue sector chroma mapping function such that, for any source color belonging to one of the two key constant-hue leaves delimiting this angular hue sector, this continuous chroma mapping function allows to map the chroma of said source color according to the key hue leaf chroma mapping function of the key constant-hue leaf to which said source color belongs. Preferably, this mapping functions are non linear polynomials.

Abstract: An aspect of present principles is directed to methods and systems for gamut mapping colors from a either a source color gamut or a content color gamut towards a target color gamut. A source hue of the source specific colors and a source hue of the content specific colors is changed towards a target hue of the corresponding target specific colors. Color gamut mapping is performed for the source colors of either the whole source color gamut or the content color gamut towards the target color gamut based on the mapped specific colors. The specific colors are selected from primary colors, secondary colors, a group of primary colors and secondary colors.

Abstract: This determination comprises: defining key constant-hue leaves such to partition the gamut mapping color space into angular hue sectors; for each key constant hue leaf, defining a key hue leaf chroma mapping function; for each angular hue sector, defining a continuous angular hue sector chroma mapping function such that, for any source color belonging to one of the two key constant-hue leaves delimiting this angular hue sector, this continuous chroma mapping function allows to map the chroma of said source color according to the key hue leaf chroma mapping function of the key constant-hue leaf to which said source color belongs. Preferably, this mapping functions are non linear polynomials.

Abstract: An aspect of present principles is directed to methods and systems for gamut mapping source colors into target colors from a source color gamut towards a target color gamut. A difference may be determined source specific colors and corresponding target specific colors. A source hue of the source specific colors is adaptively changed towards a target hue of the corresponding target specific colors based on the difference to determine mapped specific colors. Color gamut mapping is performed for the source colors of the source color gamut towards the target color gamut based on the mapped specific colors. The specific colors are selected from primary colors, secondary colors, a group of primary colors and secondary colors. The difference is based on at least one selected from the group of hue, saturation and lightness of the source specific colors and the corresponding target specific colors.

Abstract: An aspect of present principles is directed to methods and systems for gamut mapping source colors into target colors from a source color gamut towards a target color gamut. A difference may be determined source specific colors and corresponding target specific colors. A source hue of the source specific colors is adaptively changed towards a target hue of the corresponding target specific colors based on the difference to determine mapped specific colors. Color gamut mapping is performed for the source colors of the source color gamut towards the target color gamut based on the mapped specific colors. The specific colors are selected from primary colors, secondary colors, a group of primary colors and secondary colors. The difference is based on at least one selected from the group of hue, saturation and lightness of the source specific colors and the corresponding target specific colors.

Abstract: According to this method, the mapping color LUT has input colors that sample not only a source color gamut (included in an input encoding color space in which inputs colors of this LUT are encoded) but also a portion of the input encoding color space which is not included in the source color gamut. Preferably, this color LUT further includes output colors located outside the target color gamut. Accuracy of the mapping is improved, notably for source colors located near the boundary of the source color gamut.

Abstract: The invention concerns a method and a device for inserting 3D graphic animation in a 3D image, each 3D graphic element of the graphic animation being defined in size and in depth for the insertion in a determined insertion zone of said 3D image. The method comprises the step of determining for the graphic element to be inserted a depth range with a maximum allowed depth value, replacing the out of range depth values by the maximum allowed depth value when depth values of the graphic element are out of range and compensating the depth difference between the depth values of the graphic element and the maximal allowed depth value in reducing the graphic element in size proportionally to the reduction of depth for the graphic element.

Abstract: For the mapping in a non-linear color space of source colors belonging to a same constant-hue leaf, a lightness mapping function can be used which is based on a cusp lightness condition stating that a source cusp color of this leaf should be mapped into a corresponding target cusp color of this leaf. Source and target cusp colors are determined by the intersection of a source and target cusp lines with this leaf. The invention describes a method providing simplified source and target cusp lines based on a convex hull algorithm which are used instead to determine modified source and target cusp colors for the definition of the lightness mapping function.

Abstract: A method for validating a control operation to be performed by a target device through a virtual control interface. The virtual control interface is displayed by a head mounted device. A selection instruction of a first area is detected, delivering a first area. A position of gaze is detected, delivering a second area within the virtual control interface. It is detected if the first area and the second area are at least partially overlapping a same dedicated area associated to a control operation to be performed by the target device. In case of detection of an occurrence of the first area and the second area at least partially overlapping, the control operation is validated.

Abstract: The invention concerns a method and a device for inserting 3D graphic animation in a 3D image, each 3D graphic element of the graphic animation being defined in size and in depth for the insertion in a determined insertion zone of said 3D image. The method comprises the step of determining for the graphic element to be inserted a depth range with a maximum allowed depth value, replacing the out of range depth values by the maximum allowed depth value when depth values of the graphic element are out of range and compensating the depth difference between the depth values of the graphic element and the maximal allowed depth value in reducing the graphic element in size proportionally to the reduction of depth for the graphic element.

Abstract: A method for coding a block of picture data is disclosed. The method comprises the following steps: determining a prediction coefficient of a DC coefficient of a block from a DC coefficient of at least one previously reconstructed reference block, determining, for each pixel of the block, a prediction value such that the average of prediction values is proportional to the prediction coefficient to a proportionality coefficient close, calculating, for each pixel of the block, a residual value by subtracting from the picture data of the pixel the prediction value of the pixel, transforming the block of residual values by a first transform into a first block of coefficients, replacing, in the first block of coefficients, the DC coefficient by the difference between the product of the proportionality coefficient and the average of picture data of the block and the prediction coefficient, and quantizing and coding the first block of coefficients.

Abstract: In one embodiment, it is proposed a method for displaying a content through either a head mounted display device or a display device. The method is remarkable in that it comprises: detecting a presence of a display device in a field of view associated with a position of a head mounted display device; in case of detection of a presence of said display device, detecting an operating state of said display device; and if said operating state is on, meaning that said display device is displaying a content, said head mounted display device switches off, and if said operating state is off, said head mounted display device activates said display device in order to display said content on it; in case of absence of a presence of said display device, displaying a content through said head mounted display device.

Abstract: In one embodiment, it is proposed a method for validating a control operation to be performed by a target device through a virtual control interface, the virtual control interface being displayed by a head mounted device of a user. The method is remarkable in that it comprises: a step of detecting a selection instruction of a first area, delivering a selected first area; a step of detecting a position of gaze of the user, delivering a second area within the virtual control interface; a step of detecting if the selected first area and the second area are at least partially overlapping a same dedicated area associated to a control operation to be performed by said target device; and in case of detection of an occurrence of said at least partially overlapping, said method further comprising a step of validating the control operation.

Abstract: According to the compressed video data stream switching method for the transmission of a first data stream corresponding to a first video sequence, followed by, in a given switching point of this first stream, a second data stream corresponding to a second video sequence, the second data stream is modified prior to transmission, by a replacement of the bidirectional pictures with bidirectional commutation pictures of which the pictures blocks have a null residue and a null motion vector which is either forward or backward, according to the position of the blocks in the picture.

Abstract: A method for coding a block of picture data is disclosed. The method comprises the following steps: determining a prediction coefficient of a DC coefficient of a block from a DC coefficient of at least one previously reconstructed reference block, determining, for each pixel of the block, a prediction value such that the average of prediction values is proportional to the prediction coefficient to a proportionality coefficient close, calculating, for each pixel of the block, a residual value by subtracting from the picture data of the pixel the prediction value of the pixel, transforming the block of residual values by a first transform into a first block of coefficients, replacing, in the first block of coefficients, the DC coefficient by the difference between the product of the proportionality coefficient and the average of picture data of the block and the prediction coefficient, and quantizing and coding the first block of coefficients.

Abstract: The process implements an intra prediction mode which comprises: a step of motion estimation of a neighboring part of the current block, which is already coded, within the reconstructed part of the image, to get a correlated part, a step of defining a predicted block according to the correlated part and to the position of the current block regarding the neighboring part.

Abstract: The invention relates to a method for insertion of data in a block of image data, called the current block, of a sequence of images. The current block is coded or intended to be coded in the form of temporally predicted image data from prediction image data defined according to a first prediction mode According to the invention, the insertion method comprises the modification, according to the data to be inserted, of the first prediction mode into a second prediction mode different from the first prediction mode with a view to coding of the current block according to the second prediction mode, the second prediction mode being defined so that the prediction image data obtained with the second prediction mode are identical to the prediction image data obtained with the first prediction mode.

Abstract: According to the method, the second data stream is modified prior to transmission, by a replacement of the bidirectional pictures with bidirectional commutation pictures of which the pictures blocks have a null residue and a null motion vector which is either forward or backward, according to the position of the blocks in the picture. The applications relate to the transmissions and the storage of programmes, the editing.

Abstract: The method is characterized in that: if the current macroblock was coded according to the “skipped macroblock” mode and if at least one corrected coefficient block of said macroblock has coefficients non-null or greater than a predefined threshold, the coding mode of the macroblock is modified into a mode other than “skipped macroblock” and the data of the data stream is modified or added to specify this mode and the value of the coefficients.