This feature introduces a new and improved analysis algorithm that allows colorists to select the strength of highlight retention and the amount of mapping applied. Users can now choose from a predefined set of spatial filters. Selecting the “Legacy CM4 L1” option matches the analysis of the original CMv4 algorithm. Older projects from software versions created before this change will open with this selected as the default. The other options use the new analysis algorithm, each with a different strength for the spatial filter. The lowest strength filter retains the most highlight detail and applies the most mapping but should not cause any visible clipping. This option can result in producing the darkest starting point among the new analysis options. The highest strength filter often results in visibly clipped highlights, but applies the least amount of mapping, thus producing the brightest overall image when mapping to the SDR 100 nits target. The “Balanced” option is designed to permit clipping in some cases and reduce the strength of mapping, while preserving highlight detail. This is the default starting point and is recommended for all new projects. Analysis is a non-destructive process, and lost details can be restored using the trim controls.
A couple of years ago, Dolby conducted a worldwide survey of 560 industry professionals comparing Dolby Vision derived SDR versions and hand-graded SDR versions of Hollywood films and although the verdict was overwhelmingly positive toward the former, many colorists are not satisfied with Dolby’s tone mapping analysis. It remains to be seen how professionals respond to the new, improved analysis.
The Daejeon Chronicles 