NERO 4 UHD is not only a HDR-capable (accepting an HDR-encoded signal via HDMI 2.0a, HDCP 2.2) but it presents a full set of features dedicated to HDR picture display.
It offers automatic metadata recognition and an advanced calibration mode, with 4 presets to automatically fit screen sizes from 100 to 160 inches. The metadata describe the characteristics of the image being displayed (peak luminance, color gamut, etc.) and the NERO 4 UHD detects them and automatically enables its HDR mode. Nonetheless, it adjusts the image data through a process called tone mapping, for softening the clipping of high lights.
In HDR mode, the projector has 4 presets that allow customers to obtain the standard EOTF (Electro Optical Transfer Function) SMPTE S2084 behavior, with which HDR video content is packaged, suitable for 4 different types of installation, for a correct playback of HDR video materials and simplified installation The Nero 4 UHD has been designed for this behavior to be as faithful as possible to the ideal behavior it needs to have.
In addition, 4K UHD resolution, 12 bit processing and YCC 4:4:4 color coding, combined with HDR technology, allow the NERO4 to deliver unbeatable image quality. By means of its high peak luminance, inky blacks, and vibrant color gamut, NERO4 provides images where every scene is replicated with extreme realism and unprecedented detail, just as the human visual system would perceive it in the real world.
About HDR technology
In the real world, the intensity of natural light can span up to 14 orders of magnitude from night to direct sunlight. The ratio between max. and min. luminance is called dynamic range. The human eye can instantaneously perceive up to 5 orders of magnitude without adaptation. HDR (High Dynamic Range) is the ability to render a large range of luminance in a display, from extremely dark to extremely bright values, hence creating brighter whites, darker blacks and brighter colors that better match what we see in the real world.
This large dynamic range requires different display behaviors with respect to the input signal.
For this reason, all the HDR video chain has been rebuilt and, in place of the "gamma" , now an "EOTF" is used, based on the real human eye's ability to perceive differently low light and high light details (SMPTE ST2084 based On FQ - Percived Quantizer).
Proper use of HDR content therefore requires an absolute display behavior (at a given input signal level corresponds to a single and precise luminous level reproduced). This implies that, depending on the luminous flux output from the projector and the screen variations (size, material, reflectivity, etc), it is necessary to change the behavior of the projector to remain true to the EOTF for which video content was produced You want to project.