Abstract: The present embodiments relate to a method and apparatus comprising: —deriving chroma components (I) of a third image by correcting chroma components (II) of a second image according to a luma component of said second image and a reconstructed component obtained by applying a mapping function to said luma component (III) of said second image, said chroma components (II) of the second image being obtained by applying a conversion matrix to components (IV) of a first image; and —adapting coefficients of the conversion matrix which are relative to a chroma component of said third image independently of coefficients of the conversion matrix which are relative to another chroma component of said third image to ensure that there is no clipping on chroma components of the third image.

Abstract: Color mapping information can be used to transform one color to another color. The present embodiments provide a solution for representing the color mapping information using a successive application of multiple color mapping functions. Parameters for the multiple color mapping functions can be encoded into a bitstream. In one embodiment, color mapping functions are consecutively applied on their own domains of definition only. In another embodiment, the first color mapping (CRI1) is applied on its domain of definition only, but the second color mapping is applied only on samples that have been previously color mapped by CRI1 and which are also inside the domain of definition of the second color mapping function. At the decode side, the multiple color mapping functions can be reconstructed and successively applied to a decoded picture to generate another picture.

Abstract: The present principles relate to a method and device for context-adaptive binary arithmetic coding a sequence of binary symbols representing a syntax element related to video data or a syntax element relative to a video data.

Abstract: A decoding method is disclosed that comprises:—decoding (S120) a stream to obtain a decoded standard dynamic range picture and colour metadata associated with the standard dynamic range picture, wherein the colour metadata are representative at least of characteristics of a high dynamic range picture associated with the standard dynamic range picture; and—reconstructing (S130) a high dynamic range access the input stream(s) picture from the decoded standard dynamic range picture and from the colour metadata.

Abstract: A method of color mapping a video signal represented in a first color volume from color mapping data to be applied on a video signal represented in a second color volume is disclosed. The method comprises: color mapping (14) said video signal represented in a first color volume from said first color volume into said second color volume in the case where said first and second color volumes are different; and color mapping (16) said color mapped video signal based on said color mapping data.

Abstract: The present disclosure generally relates to a method and device of converting a HDR version of a picture to a SDR version of this picture. The method is characterized in that it converts the HDR version to the SDR version of the picture according to: a first indicator that indicates the presence of color mapping parameters; a second indicator that indicates whether a device is configured to convert the HDR version to the SDR version of the picture by taking into account said color mapping parameters; and a third indicator that indicates whether converting without taking into account said color mapping parameters is inhibited.

Abstract: Significance flags in advanced video compression systems are coded using contexts adaptive to the last N significance flags coded taken in a scanning order. One embodiment uses the last N significance flags in scanning order as a predictor to determine which of a plurality of sets of significance flag contexts to use for coding subsequent significance flags. A second embodiment uses the last N significance flags in scanning order as a predictor in order to modulate the probability value associated with significance flag contexts that are used to code significance flags for future coding.

Abstract: The present principles relates to a method and device for reconstructing an High-Dynamic-Range image represented by one reconstructed High-Dynamic-Range luma component (??) and two reconstructed High-Dynamic-Range chroma components (Û?, (I)) from a Standard-Dynamic-Range image represented by a Standard-Dynamic-Range luma component (y?, y?1) and two Standard-Dynamic-Range chroma components (u?, v?). The method is characterized in that the method comprises: inverse-mapping (22) said Standard-Dynamic-Range luma component (y?, y?1) to obtain said reconstructed High-Dynamic-Range luma component (??); and correcting (33) said two Standard-Dynamic-Range chroma components (u?, v?) to obtain said two reconstructed High-Dynamic-Range chroma components (Û?, (I)) according to said Standard-Dynamic-Range luma component (y?, y?1) and said reconstructed High-Dynamic-Range luma component (??).

Abstract: A method for decoding a picture block is disclosed. The decoding method comprises: decoding decoded data, and information for identifying a reconstructed reference picture in a decoder picture buffer; reconstructing another reference picture from the identified reconstructed reference picture identified by the information and from the decoded data; replacing in the decoder picture buffer the reconstructed reference picture identified by the information with the another reference picture; and reconstructing the picture block from the another reference picture.

Abstract: A method for encoding a LUT defined as a lattice of vertices is disclosed. At least one value is of each vertex of the lattice. The method comprises for a current vertex: predicting the at least one value of said current vertex from another value which is for example obtained from reconstructed values of neighboring vertices; and encoding in a bitstream at least one residue computed between the at least one value of the current vertex and its prediction in a bitstream.

Abstract: A method for encoding a LUT defined as a lattice of vertices is disclosed. At least one value is of each vertex of the lattice. The method comprises for a current vertex: predicting the at least one value of said current vertex from another value which is for example obtained from reconstructed values of neighboring vertices; and encoding in a bitstream at least one residue computed between the at least one value of the current vertex and its prediction in a bitstream.

Abstract: A method and device for reconstructing image data is provided that is representative of an original image data from a decoded image data and parameters obtained from a bitstream, the parameters having been processed from said original image data. The method provides a desaturating of a luma component, an inverse-mapping of desaturated luma component and a correction of chroma components. These operations are being modulated according to the value of a single modulation factor mod representative of a peak luminance of a presentation display on which the reconstructed image is intended to be displayed, a peak luminance of a particular range image and a peak luminance of the original image data or the mastering display used to grade the original image data.

Abstract: The present disclosure relates to methods, apparatus or systems for generating, transmitting and decoding a backward compatible immersive video stream. The stream is carrying data representative of an immersive video, composed of a frame organized according to a layout having a first area encoded according to a rectangle mapping, a second area encoded according to a mapping transitory from the rectangular mapping to an immersive mapping and a third area encoded according to the immersive mapping. In order to be backward compatible, the stream further includes first information representative of the size and the location of the first area within the video frame, and second information having at least the type of the selected layout, the field of view of first part, of the size of the second area within the video frame and a reference direction.

Abstract: A method for color processing in view of displaying a video image on a display device is described. The method includes retrieving a spectral power distribution associated with at least one group of light elements of the display device, the group of light elements displaying a color component of the video image to be displayed; computing, in a range of the spectral power distribution, called range of noxiousness, a noxiousness value representative of the noxiousness of the light emitted by the group of light elements of the display device; and comparing the noxiousness value to a bound value of noxiousness. If the noxiousness value is greater than the bound value, the content of the image is modified or the display control parameters of the display device are modified such that the noxiousness value becomes less than the bound value.

Abstract: A method for encoding a colour transform is disclosed that comprises encoding first parameters representative of video signal characteristics of colour output decoded pictures remapped by said at least one color transform; and encoding second parameters representative of said at least one colour transform.

Abstract: A method of color mapping a video signal represented in a first color volume from color mapping data to be applied on a video signal represented in a second color volume is disclosed. The method comprises: color mapping (14) said video signal represented in a first color volume from said first color volume into said second color volume in the case where said first and second color volumes are different; and color mapping (16) said color mapped video signal based on said color mapping data.

Abstract: The present disclosure generally relates to a method and device of encoding a color picture having color components (Ec) comprising obtaining (11) a luminance component (L) and two chrominance components (C1, C2) from the color picture to be encoded. The method for encoding a color picture having color components comprising obtaining at least one chrominance component from the color picture to be encoded, characterized in that the method further comprises: determining a first factor based on the value of each pixel (i) of said luminance component; obtaining at least one final chrominance component by scaling said at least one chrominance component by said first factor; and encoding (13) said at least one final chrominance component.

Abstract: A method for encoding a colour transform is disclosed that comprises encoding first parameters representative of video signal characteristics of colour output decoded pictures remapped by said at least one color transform and encoding second parameters representative of said at least one colour transform.

Abstract: A method of color mapping a video signal represented in a first color volume from color mapping data to be applied on a video signal represented in a second color volume is disclosed. The method comprises: color mapping (14) said video signal represented in a first color volume from said first color volume into said second color volume in the case where said first and second color volumes are different; and color mapping (16) said color mapped video signal based on said color mapping data.

Abstract: To preserve backward compatibility with a non-HDR device or service, an HDR picture may be represented using a modulation value and an SDR picture representative of the HDR picture. The modulation value and the SDR picture can then be encoded into the bitstream. At the receiving side, the modulation value and the SDR picture can be decoded. Based on the modulation value, the SDR picture can be mapped to a decoded HDR picture. For a non-HDR device or service, the modulation value information may be discarded and only the SDR picture is decoded. In particular, the modulation value may be implicitly signaled, using quad-tree representation information, intra coding information, inter partition mode information or motion vector residual information.