Apparatuses and methods for improved encoding of images for better handling by displays

A video encoding apparatus arranged to encode, in addition to high dynamic range video data, descriptive data comprising at least one change time instant (TMA_1) indicating a change in time of a characteristic luminance (CHRLUM) of successive input images of an input video, which characteristic luminance summarizes a set of luminances of pixels in an input image of the input video, the encoding apparatus comprising:

• an encoder arranged to encode and output output video data (VID) comprising initial luminances (Lin*);
• an encoder arranged to encode in the descriptive data at least one indication (ALCORR, (TYPE)) of a reprocessing strategy of the initial luminances of the pixels of the output video to be performed by an apparatus (112, 110) using the video data and descriptive data, to obtain output luminances, which at least one indication of a reprocessing strategy comprises a mathematical algorithm for calculating a deviation strategy for changing the initial luminances (Lin*), prescribed over at least one of successive time instants at or after the at least one change time instant (TMA_1);
• an output arranged to output the descriptive data.

A method of decoding high dynamic range video data (VID) and descriptive data (DED) which is additional to the video data (VID), which video data (VID) comprises initial luminances (Lin*), and the descriptive data comprising at least one change time instant (TMA_1) indicating a change in time of a characteristic luminance (CHRLUM) of the video data, which characteristic luminance summarizes a set of luminances of pixels in an image of the video data, and the method further decoding from the descriptive data at least one indication (ALCORR, (TYPE)) of a reprocessing strategy comprising a mathematical algorithm for calculating a deviation of the initial luminances (Lin*), prescribed over successive time instants comprising at least the at least one change time instant (TMA_1), the method further comprising using the mathematical algorithm to calculate output luminances from the initial luminances (Lin*) of images at or after the at least one change time instant (TMA_1).

A video decoding apparatus arranged to decode video data (VID) comprising initial luminances (Lin*) and arranged to decode, related to the video data (VID) descriptive data comprising at least one change time instant (TMA_1) indicating a change in time of a characteristic luminance (CHRLUM) of the video data, which characteristic luminance summarizes a set of luminances of pixels in an image of the video data, and the video decoding apparatus (600) being arranged to decode from the descriptive data at least one indication of a reprocessing strategy which comprises a mathematical algorithm for calculating a deviation strategy for changing the initial luminances (Lin*), prescribed over at least one of successive time instants comprising the at least one change time instant (TMA_1);

• and the video decoding apparatus (600) being arranged to transform the initial pixel luminances of images at or after the at least one change time instant by applying the mathematical algorithm to obtain output luminances.