Please note that this will enable by default the "Enable Tone Mapping Preview" checkbox in the HDR10+ tab of the Color page.
MKVTOOLNIX 4.8.0 TV
To determine this value, personally I started from a low value of 500 nits, increased this value by steps of 100, and stopped when I noticed that my TV monitor was starting to adjust (darken) the image to accomodate higher luminosity data (this happened passing from 1000 to 1100, so I set this value If unsure, I would recommend to keep this value which is also the default suggestion made by DVR. For instance, I used the value I found in a technical review of my Samsung LED TV screen (550 nits: yes I know, not so good).
MKVTOOLNIX 4.8.0 PC
** On my Mac, I installed it using Homebrew, which is a very convenient way to get it. And an HDMI cable which is at least compliant with specs 2.0a. Also, to use UltraStudio Monitor 3G, make sure you have a real Thunderbolt 3 cable, not just USB. * Even though this is far from optimal (I know!), and since I am just an amateur and not a pro, to grade in HDR I use my Samsung LED TV: I got a Blackmagicdesign UltraStudio Monitor 3G to connect it to my Mac, it costs ~100 bucks. mkvmerge (available via mkvtoolnix** free, may be not should be nomore necessary if DVR embeds correct HDR10 metadata, which is not always the case in my experience).MediaInfo (free, but not a strict requirement, just useful to check that the final result is ok).
MKVTOOLNIX 4.8.0 FREE
MLV APP (or any other free tool to convert MLV to Cinema DNG's).Requirements (apart from camera with ML of course) Check for final video to embed correct HDR10 metadata (as DVR may fail in my experience): if not, correct HDR10 metadata using mkvmerge.Taking advantage of FastFlix (based on ffmpeg, in turn based on x265), render an H.265 Main10 HDR10 video with HDR10+ dynamic metadata built-in.HDR10+ metadata (JSON file) as prepared by DVR.HDR10 graded footage as high-quality lossless Apple ProRes master.Import DNG in DaVinci Resolve Studio (DVR in what follows) and grade HDR footage using an external HDR monitor (even your TV display could do the job, more on this below).Convert MLV to DNG (via MLV APP or any other tool capable of that).Thought I'd share my current workflow for rendering HDR10+ videos.