System for handling multiple HDR video formats

Because there are currently probably more than necessary different HDR video coding methods appearing, it is expected that practical communicated HDR videos may in several future scenarios consist of a complicated mix of differently encoded HDR video segments, which may be difficult to decode unless one has our presently presented video decoder (341) arranged to decode a high dynamic range video consisting of temporally successive images, in which the video is composed of successive time segments (S1, S2) consisting of a number of temporally successive images (I1, I2) which have pixel colors, which pixel colors in different time segments are defined by having lumas corresponding to pixel luminances according to different electro-optical transfer functions (EOTF), wherein the images in some of the segments are defined according to dynamically changeable electro-optical transfer functions which are transmitted as a separate function for each temporally successive image, and wherein the images in other segments have lumas defined by a fixed electro-optical transfer function, of which the information is co-communicated in data packages (DRAM) which are transmitted less frequently than the image repetition rate, and wherein at least one of said data packages (DRAM) characterizing the electro-optical transfer function of the image pixel lumas after a moment of change (t1) between a first and a second segment is transmitted prior to the moment of change (t1); and similarly a corresponding encoder which composes the segmented video stream assuring that at least one correct package (DRAM) describing the EOTF according to which the lumas of a later video segment is coded is received by receivers before the change to a different HDR encoding method segment.