I’m relatively new to ACES but I’m really trying to make it work for new projects. I also hit the wall on trying to incorporate DJI D-Log footage in Davinci Resolve. It seems odd to me that there isn’t an ACES input transform for this. Almost every television series or feature film I work on has aerials and the majority are DJI and much of the footage is D-Log. Aerial footage is not just a consumer happening, it is serious business in the film and television world. The best workaround I’ve found in Resolve is to apply no input transform and apply and Resolve Color Transform node to each clip used to convert from D-Gamut. This does not help much with gamma, as then clips need to be seriously dialed in to achieve the correct contrast.
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Both primaries and transfer function (gamma) should be converted in the process if you use the CST method. Everything else on the CST should be turned off/set to none except White Point Adaptation.
An alternative is to add a custom IDT to your Resolve via this handy tool.
But the link to directly download it was already posted here.
For Windows you need to place it here:
C:\Users[your user name]\AppData\Roaming\Blackmagic Design\DaVinci Resolve\Support\ACES Transforms\IDT
For Mac I don’t know from the top of my head but a quick google search should give you that.
If contrast is still far off from what it’s supposed to be I would suspect that the source isn’t shot in DLog but some other DJI variant that is already transformed to Rec.709 but with different a more sophisitacted curve. Think ‘cinelike’ picture profiles etc. Those custom transfer functions can’t really be defined and mathematically converted so in those cases treating them as Rec.709/2.4 is the best approach and work from there.
Thanks for this, Shebbe. I’ll give this a try and see where I get to. You’ve been very helpful since I joined the ACES community and I appreciate your help.
This looks like what I’ve been looking for to grade D-Log. Can you take a step back for me, if you have time. I’m a colorist, but I’m not technical enough to understand where to install this file? I’m looking through the Resolve library right now looking for an ACES folder that contains input transforms and I don’t see it. Maybe that is not where I should be putting it, anyway, but if you could let me know, would sure appreciate the extra coaching. Thanks
I’ve looked at this tool that’s posted but I don’t understand how to use it. I don’t see any instructions or guidance. I downloaded the ACES_DLog_DGamut.ctl that you are supposed to change to .dctl but where does this go. I’ve looked through libraries for Resolve and don’t see an ACES input transform folder. I would just pay someone to provide me an input transform for D-Log and yes it is definitely D-Log. I’m working on 2 TV series and a feature film, so I don’t have time to be experimenting and need solutions. I committed to ACES for one of the series and am a bit sorry I did. It doesn’t feel good to me and qualifying colors for secondary work is very poor. Resolve’s color tools do not seem to be ACES aware in my opinion. The finest eyedropper selection results in a near full image selection that must be dialed in painstakingly.
Hey Jack,
Perhaps you didn’t fully read my previous post but I already gave you the link to where you can download the .dctl file and also where to put it if you’re Windows based. For Mac you could also google to find the proper folder, I don’t know it from the top of my head.
Hope that helps.
It goes in the DaVinci folder in the User’s Library (not system library):
/Users/user/Library/Application Support/Blackmagic Design/DaVinci Resolve/ACES Transforms/IDT
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Thanks for this Scott. I didn’t get notified of your response. I found the right folder on Mac based on your directory information. Strangely both the IDT and ODT folders are empty, so these must be folders available for additional or custom transforms? Anyway, I’ll give this a try.
Just circling back to this now. Sorry, I didn’t see your further response. Not sure why I didn’t get a notification so I didn’t think you replied until I check. Scott gave me the Mac directory so now I’ll give this a try. I do like the look of the ACES IDT DCTL TOOL and sometime if you have time, I’d like to learn how to use this. I tried a google search on this tool but didn’t find anything yet.
I did drop the file into the Mac folder and it does not show up in ACES input transforms within Resolve. When I contextually select IDT the folder is empty. I did rename the extension as you mentioned. Sorry, maybe I’m still doing something incorrectly.
That’s correct!
Sorry I forgot to mention, for the DCTL files to work as ACES Transforms an extra line of code is needed. Open the .dctl in a text editor, place this at the top of the code and save it again.
DEFINE_ACES_PARAM(IS_PARAMETRIC_ACES_TRANSFORM: 0)
That should do the trick.
I just tried that and it works. It looks perfect. Thanks again for all your help.
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Thanks for all the valuable information on this thread.
What about DJI D-Log M grading? Can anyone confirm if DJI has ever released the technical info for D-Log M, which is more and more used in their cameras? It would be most useful to be able to build an accurate IDT/DCTL for D-Log M, which is different from D-Log.
As far as I’m aware D-Log M is not an true log encoding and more of a custom curve ‘flat’ profile. Linearizing that curve wouldn’t be that simple. For grading most people, including me, simply treat this as a Rec.709 image, adding contrast and saturation to get to the desired result.
D-Log M is typically used on the more budget devices they offer or the ones that aren’t capable of recording high bitrate 10bit files needed for log encoding.
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Thanks Shebee. In my case, I’ve got files from both DJI’s Air 3 and Mini 4 Pro. Their all 10bit 4:2:0 HEVC encoded. Read some posts on DJI Forum talking about using Rec2100 HLG or ARIB STD-B67 HLG as input gamma…
Anyway, no news on having the specs published by DJI, as they did with the D-Log D-Gamut white paper?
To look further into this, search DJI Forum for the thread “Please Release the DLOG-M Color Space (DCTL/IDT/ODT) Information!”
My goal, and the bottom line of this question, is to be able to work correctly in ACES with material from D-Log M encoded clips from DJI.
The project I’m working on right now has several dozens of these…
I just posted on the logik forum - I’m going to copy paste what I wrote:
Ignoring the 1.4 exposure compensation and the header-hack, I get a match between:
- Resolve (Rec.709/Linear to D-Gamut/D-Log (…to AWG3/LogC3) - via colorspace transform node)
- Resolve (Rec.709/Linear to D-Gamut/D-Log - via DJI’s 1D LUT)
- Baselight (CGI Linear / Rec.709 to AWG3/LogC3)
- Transkoder/OSD (auto debayers to AWG3/LogC3)
- Silverstack Lab (RAW set to "D-Gamut/D-Log)
Now… with the header trick**, the actual “debayer to D-Gamut/D-Log” in Resolve is ever so slightly different, dare I say better?.. And no Color temp/Tint tweaking can get the Rec709/Lin to match this method.
What is Blackmagic doing? Did they profile the sensor themselves? How is it that no other software can replicate Resolve’s D-Gamut/D-Log debayer?
I’ve also tried the photo-based softwares (Lightroom, Affinity, RAWTherapee, etc.), and those are the furthest off (having no straightforward way to get a Log image…)
I even compiled rawtoaces and that did not get me anywhere near the baseline I was hoping for.
Fascinating. Exhausting.
** header trick:
exiftool -UniqueCameraModel=FC4280 -m the.dng
Link 1
Link 2
Not that I’m aware of.
Thanks to @jeeroome’s post I remember this useful tool. It seems who made this did profile DLog-M so perhaps you can make it work via creating a LUT for it. If it doesn’t seem to play nice with the ranges maybe converting to a different log space instead to keep the LUT between 0-1 and convert further in Resolve.
Can’t speak of the validity of the tools but I also found this and this.
They offer a demo version so you could give it a spin and see if it’s suitable.
On @jeeroome 's topic…
A while ago I encountered odd differences in debayer behavior with DJI DNGs to ‘native’ DGamut/DLog vs any other space. Perhaps these differences remain when ‘hacking the header’ on non DJI files. It only makes me think that Resolve’s handling may be actually less accurate but I don’t know enough about the subject to do my own testing and verifications.
Thanks @shebbe , that’s quite the multi-forum rabbit hole! I just pinged the users in that BMD thread for their input.
I would love to find some ground truth debayer…
Facing the reality of a brand that refuses to disclose crucial technical information, I think the best we can do as professionals is to work with what they give us. Well aware that, in this case, what we have is a LUT that greatly reduces the proclaimed potential of the original D-Log M 10bit files.
I won’t stop working in ACES just because DJI doesn’t allow us to take the best out of their footage.
Let’s hope bad publicity will make them think twice…