I'm working on another HDR project, and with the newest beta of Voukoder I'm having some issues with color in HDR. Working with HDR in Premiere is a bit of a weird thing. Basically, you have to import in the raw, unprocessed 10bit footage, which Premiere will assume as rec709 color. This will look all washed out and incorrect, unless you have an HDR monitor that can take this raw ST2084 encoded footage, and display it in HDR correctly, which I have.
So, Premiere thinks you're working with rec709 footage, even though the footage is actually rec2020 underneath. This is necessary, because if you give Premiere an actual correctly-flagged rec2020/st2084 video, it will convert those colors into something that will display more correctly on an SDR display, but can not be encoded to HDR correctly aside from Adobe's own codec, and can not be displayed on an HDR monitor correctly, for monitoring while editing.
When I select rec2020 for output in Voukoder, there appears to be some color space conversion going on, which causes a serious shift in colors, making everything appear greenish. I'm guessing Voukoder sees the footage as rec709, and wants to convert the colors to rec2020, but even though Premiere interprets it as rec709, the footage is actually rec2020 and so should need no conversion. Here is a raw frame as it appears in Premiere on a normal monitor:
and here is how that frame gets encoded with Voukoder set to rec2020:
Right away, even in the unprocessed raw footage you should be able to tell that colors appear more washed out, and more green tinted. But here are the same two images, with HDR-to-SDR tonemapping applied, to give you a more "correct" look at how the images would display:
That's a major shift in color, and looks really bad.
I actually noticed this issue before, while encoding my previous project in Voukoder 2.0.8. However, that version had two different options for color space. In the normal Premiere window, I set color space to rec709, because that's essentially what Premiere assumes it is, but then in Voukoder's advanced x265 settings I set these options that specified to encode in rec2020 and ST2084/PQ
This allowed the raw image to pass through mostly unaffected (although there's always a slight tint seemingly applied to all encodes I make with x264 & x265 from Premiere, voukoder or not). These options are apparently gone now, in favor of a single color space selector in the main window.
Since Voukoder appears to correctly assume that the transfer characteristics (ST2084/PQ) are inherent to the source, and not something that needs to be converted, it should do the same for color space. When you select color space, you should be selecting what the source already is, not what you want to convert it to.
I hope this is something that could be fixed somewhat soon, but if not I can always go back and install the older version which worked better.