Abstract: Encoding can involve correcting chroma components representing the chroma of an input image according to a first component representing a mapping of the luminance component of said input image used for reducing or increasing the dynamic range of said luminance component, and a reconstructed component representing an inverse mapping of said first component. At least one correction factor according to said at least one scaled chroma components can also be obtained and transmitted. Decoding can involve scaled chroma components being obtained by multiplying chroma components of an image by at least one corrected chroma correction function depending on said at least one correction factor. Components of a reconstructed image can then be derived as a function of said scaled chroma components and a corrected matrix that depends on an inverse of a theoretical color space matrix conversion and said at least one correction factor.

Abstract: Different implementations are described, particularly implementations for processing a medium dynamic range video signal are presented. In a method for processing such a video signal a medium dynamic range video signal and associated metadata are received, wherein the metadata include data representative of a peak luminance value of the medium dynamic range video signal. In addition, data representative of a peak luminance value of a presentation display are received. It is determined whether the peak luminance value of the medium dynamic range video signal is greater or lower than the peak luminance value of the presentation display. A processor is configured based on the determination, wherein the processor has a first mode to reconstruct a high dynamic range video signal based on a received standard dynamic range video signal and associated metadata, and a second mode to optimize a received high dynamic range video signal for the rendering device.

Abstract: A method comprising modifying a color correction function intended to correct initial chroma components of a current image to obtain normalized corrected chroma components for avoiding the clipping of the initial chroma components while maintaining saturation and preserving hue.

Abstract: The present disclosure relates to a method and device for obtaining a second image from a first image when the dynamic range of the luminance of the first image is greater than the dynamic range of the luminance of the second image. The disclosure describes deriving at least one component representative of the colors of the second image from the first image, and maximizing at least one derived component according to a maximum value depending on a linear-light luminance component of the first image.

Abstract: At least one embodiment obtain a method for reconstructing an image from metadata representing a given color space, comprising mapping said given color space to a candidate color space which encompasses in its convex hull all the primaries of the given color space; and reconstructing the image using said candidate color space.

Abstract: The present disclosure relates to a method and device for obtaining a second image from a first image when the dynamic range of the luminance of the first image is greater than the dynamic range of the luminance of the second image. The disclosure describes deriving at least one component representative of the colors of the second image from the first image, and maximizing at least one derived component according to a maximum value depending on a linear-light luminance component of the first image.

Abstract: A method for decoding an image enables to preserve artistic intent at the final rendering stage by adjusting the image to luminance characteristics of the content and of the presentation display that will display the image. Values representative of luminance of both the image and the display device are obtained. Parameters of a display adaptation function are adjusted according to these values and the adjusted display adaptation function is used to decode the image. In at least one embodiment, the adjusted display adaptation function relates to a tone mapping function. Corresponding apparatus implementing the method is also described.

Abstract: The present embodiments obtain chroma components representative of the chroma components of an output image from color components representative of an input image, and if a value of a pixel in at least one of said chroma components exceeds a given value, modify the value of said pixel in at least one of said color components in such a way that the value of said pixel in said at least one of said chroma components is lower than or equals to said given value.

Abstract: Described are methods and devices for applying a color gamut mapping process on a first image to generate a second image, where the content of the first and second images is similar but the respective color spaces of the first and second images are different. The color gamut mapping process may be controlled using a color gamut mapping mode obtained from a bitstream where the color gamut mapping mode belongs to a set comprising at least two preset modes and an explicit parameters mode. If the obtained color gamut mapping mode is the explicit parameters mode and the color gamut mapping process is not enabled for the explicit parameters mode, the color gamut mapping process may be controlled by a substitute color gamut mapping mode determined from additional data.

Abstract: Different implementations are described, particularly implementations for processing a medium dynamic range video signal are presented. In a method for processing such a video signal a medium dynamic range video signal and associated metadata are received, wherein the metadata include data representative of a peak luminance value of the medium dynamic range video signal. In addition, data representative of a peak luminance value of a presentation display are received. It is determined whether the peak luminance value of the medium dynamic range video signal is greater or lower than the peak luminance value of the presentation display. A processor is configured based on the determination, wherein the processor has a first mode to reconstruct a high dynamic range video signal based on a received standard dynamic range video signal and associated metadata, and a second mode to optimize a received high dynamic range video signal for the rendering device.

Abstract: The present disclosure relates to a method and device for obtaining a second image from a first image when the dynamic range of the luminance of the first image is greater than the dynamic range of the luminance of the second image. The disclosure describes deriving at least one component representative of the colors of the second image from the first image, and maximizing at least one derived component according to a maximum value depending on a linear-light luminance component of the first image.

Abstract: A device and a method for outputting video content for display on a display. At least one processor displays a first video content on the display, receives a second video content to display, obtains a first luminance value for the first video content, extracts a second luminance value from the second video content, adjusts a luminance of a frame of the second video content based on the first and second luminance values and outputs the frame of the second video content for display on the display. The video content can comprise frames and a luminance value can be equal to an average frame light level for the most recent L frames of the corresponding video content. In case a luminance value is unavailable, a Maximum Frame Average Light Levels of the first video content and the second video content can be used instead.

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: A medium dynamic range video signal and associated metadata are received, wherein the metadata include data representative of a peak luminance value of the signal. The medium dynamic range video signal is processed in a first mode to reconstruct a high dynamic range video signal based on a received standard dynamic range video signal and associated metadata if the peak luminance value of the medium dynamic range video signal is smaller than the peak luminance value of a presentation display, and in a second mode to optimize a received high dynamic range video signal for a rendering device if the peak luminance value of the medium dynamic range video signal is greater than the peak luminance value of the presentation display.

Abstract: A method or device for reconstructing image data representative of original image data from decoded image data and parameters obtained from a bitstream is described. The parameters having been processed from the original image data. The method includes checking if parameters are lost, corrupted or not aligned with the decoded image data whose graphics or overlay is added to, when at least one of the parameters is lost, corrupted or not aligned with the decoded image data whose graphics or overlay is added to; selecting a recovery mode according to an information data indicating how the parameters have been processed; and recovering the at least one lost, corrupted or not aligned parameter by applying the selected recovery mode, the reconstruction of image data then taking also into account the recovered parameters.

Abstract: A method or device for reconstructing image data representative of original image data from decoded image data and parameters obtained from a bitstream is described. The parameters having been processed from the original image data. The method includes checking if parameters are lost, corrupted or not aligned with the decoded image data whose graphics or overlay is added to, when at least one of the parameters is lost, corrupted or not aligned with the decoded image data whose graphics or overlay is added to; selecting a recovery mode according to an information data indicating how the parameters have been processed; and recovering the at least one lost, corrupted or not aligned parameter by applying the selected recovery mode, the reconstruction of image data then taking also into account the recovered parameters.

Abstract: The present disclosure relates to a method and device for obtaining a second image from a first image when the dynamic range of the luminance of the first image is greater than the dynamic range of the luminance of the second image. The disclosure describes deriving at least one component representative of the colors of the second image from the first image, and maximizing at least one derived component according to a maximum value depending on a linear-light luminance component of the first image.

Abstract: A method for decoding an image enables to preserve artistic intent at the final rendering stage by adjusting the image to luminance characteristics of the content and of the presentation display that will display the image. Values representative of luminance of both the image and the display device are obtained. Parameters of a display adaptation function are adjusted according to these values and the adjusted display adaptation function is used to decode the image. In at least one embodiment, the adjusted display adaptation function relates to a tone mapping function. Corresponding apparatus implementing the method is also described.

Abstract: The present principles relates to a method and device for reconstructing an HDR image by applying a reconstruction process on a SDR image whose the content is similar to the content of the HDR image but the dynamic range of the luminance values of said SDR image is lower than the dynamic range of the luminance values of said HDR image, said reconstruction process requiring parameters obtained from a bitstream. The method is characterized in that the method further comprises determining whether all the required parameters are available from the bitstream and recovering the lost or corrupted parameters from additional data, said reconstruction process further taking into account said recovered parameters.

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.