HDR image data are successfully transmitted between devices. High dynamic range image data are sent to an external device. Transmission scheme information and/or gamma correction information for the high dynamic range image data are sent to the external device. The external device can easily understand, for example, what kind of transmission scheme and what kind of gamma correction scheme are used for the sent high dynamic range image data. Therefore, the high dynamic range image data can be successfully transmitted.

HDR image data are successfully transmitted between devices. High dynamic range image data are sent to an external device. Transmission scheme information and/or gamma correction information for the high dynamic range image data are sent to the external device. The external device can easily understand, for example, what kind of transmission scheme and what kind of gamma correction scheme are used for the sent high dynamic range image data. Therefore, the high dynamic range image data can be successfully transmitted.

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.

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.

A processor for video coding receives a full-frame rate (FFR) HDR video signal and a corresponding FFR SDR video signal. An encoder generates a scalable bitstream that allows decoders to generate half-frame-rate (HFR) SDR, FFR SDR, HFR HDR, or FFR HDR signals. Given odd and even frames of the input FFR SDR signal, the scalable bitstream combines a base layer of coded even SDR frames with an enhancement layer of coded packed frames, where each packed frame includes a downscaled odd SDR frame, a downscaled even HDR residual frame, and a downscaled odd HDR residual frame. In an alternative implementation, the scalable bitstream combines four signals layers: a base layer of even SDR frames, an enhancement layer of odd SDR frames, a base layer of even HDR residual frames and an enhancement layer of odd HDR residual frames. Corresponding decoder architectures are also presented.

A processor for video coding receives a full-frame rate (FFR) HDR video signal and a corresponding FFR SDR video signal. An encoder generates a scalable bitstream that allows decoders to generate half-frame-rate (HFR) SDR, FFR SDR, HFR HDR, or FFR HDR signals. Given odd and even frames of the input FFR SDR signal, the scalable bitstream combines a base layer of coded even SDR frames with an enhancement layer of coded packed frames, where each packed frame includes a downscaled odd SDR frame, a downscaled even HDR residual frame, and a downscaled odd HDR residual frame. In an alternative implementation, the scalable bitstream combines four signals layers: a base layer of even SDR frames, an enhancement layer of odd SDR frames, a base layer of even HDR residual frames and an enhancement layer of odd HDR residual frames. Corresponding decoder architectures are also presented.

A method, computer program, and computer system for video coding is provided. Video data including one or more quantized coefficients is received. One or more index values associated with the quantized coefficients are mapped to one or more step values based on an exponential mapping. The video data is decoded based on the one or more step values.

The present technique relates to a file generation apparatus, a file generating method, a file reproduction apparatus, and a file reproducing method capable of enabling a user to enjoy an HDR image. HDR information designated by HDR designating information is acquired from a file storing a track of a stream including the HDR information which is configured with feature information representing features of luminance of an HDR (high dynamic range) image having a dynamic range higher than that of an STD (standard) image and conversion information representing a conversion rule of converting the one of the STD image and the HDR image into the other and a target track including the HDR designating information designating the HDR information which is to be applied to the target track of interest in the HDR information of the track. The present technique can be applied to the case of acquiring HDR information which is to be applied to an image of a subtitle or the like stored in, for example, an MP4 file.

The present technique relates to a file generation apparatus, a file generating method, a file reproduction apparatus, and a file reproducing method capable of enabling a user to enjoy an HDR image. HDR information designated by HDR designating information is acquired from a file storing a track of a stream including the HDR information which is configured with feature information representing features of luminance of an HDR (high dynamic range) image having a dynamic range higher than that of an STD (standard) image and conversion information representing a conversion rule of converting the one of the STD image and the HDR image into the other and a target track including the HDR designating information designating the HDR information which is to be applied to the target track of interest in the HDR information of the track. The present technique can be applied to the case of acquiring HDR information which is to be applied to an image of a subtitle or the like stored in, for example, an MP4 file.

A backward reshaping mapping table is initially generated as an inverse of a forward reshaping mapping table. The backward reshaping mapping table is updated by replacing the content-mapped luminance codewords with forward reshaped luminance codewords generated by applying a luminance forward mapping to the sampled luminance codewords. The luminance forward mapping is constructed from the forward reshaping mapping table. The backward reshaping mapping table and the luminance forward mapping are used to generate backward reshaping mappings for creating a reconstructed image from a forward reshaped image. The forward reshaped image is encoded, in a video signal, along with image metadata specifying the backward reshaping mappings. A recipient device of the video signal applies the backward reshaping mappings to the forward reshaped image to create the reconstructed image of the second dynamic range.