Grading D-Log M in Resolve

[Hands Down]

I'm experimenting with the D-Log M format in the new Mini 4 Pro. I'm pretty new to log formats. I have tried a couple of different techniques in Davinci Resolve Studio.

The first was to apply the D-Log M to REC.709 LUT from DJI's site. The second was to use a color space transform as shown in the Casey Faris video below. Using each of these techniques, and after doing some further adjustments with the color wheels and window functions, I was able to get a result I was happy enough with. I felt like the D-Log M format allowed me to recover quite a bit of detail that was underexposed from the Mini 4's auto exposure choosing to expose for the sky, compared to the normal 8-bit format.

But my question is: would either of these techniques (LUT vs. color space transform) be the preferred workflow for D-Log M? I'm not even really sure the DJI D-Gamut and DJI D-Log choices in the CST input drop-downs are intended for D-Log M, since it isn't a true log format.

Any thoughts?

 

[akdrone]

I think there is no "right" way and have heard various experts explain that using a LUT from within the Info Inspector is best and others say it's best to add a custom LUT through the Effects tab. When you use the Inspector everything that happens (color grading) happens AFTER the LUT. With the use of a Custom LUT you can affect the image before the custom LUT. That's the primary difference between them.

 

[Hands Down]

Thanks for the reply and tips! There are SO many color options in Resolve it can be a bit overwhelming.

I ran across this post from here from a few months back, and tried the suggestion from the video.

So essentially:
Use Color Management with these settings (found in project settings)


Then right click on the clip in the Color page and set the Input Color Space for the D-Log M clip to:

HLG-->REC.2020 HLG ARIB STD-B67



I felt like this gave me the most natural and pleasing result, while requiring the least amount of tweaking color wheels, curves, and window functions compared to anything I've tried so far.

HLG seems a weird choice given that the footage is D-Log M and not HLG. But yet the result is good.

Using the DJI LUT actually gave a good result too, except in shots where there was a high dynamic range. That required a lot of additional adjustments. Like, for example, in this frame you can see the ground was very dark using just the LUT. With Color Management, it's actually pretty well exposed, as is the sky, and there is some room to bring up the overall exposure if I want to.

So for comparison, with no other adjustments applied:

Unprocessed D-Log M


DJI D-Log M to REC.709 LUT applied


Davinci YRGB Color Management using HLG ARIB Input Color Space

 

[JavaJack]

I'm experimenting with the D-Log M format in the new Mini 4 Pro. I'm pretty new to log formats. I have tried a couple of different techniques in Davinci Resolve Studio.

The first was to apply the D-Log M to REC.709 LUT from DJI's site. The second was to use a color space transform as shown in the Casey Faris video below. Using each of these techniques, and after doing some further adjustments with the color wheels and window functions, I was able to get a result I was happy enough with. I felt like the D-Log M format allowed me to recover quite a bit of detail that was underexposed from the Mini 4's auto exposure choosing to expose for the sky, compared to the normal 8-bit format.

But my question is: would either of these techniques (LUT vs. color space transform) be the preferred workflow for D-Log M? I'm not even really sure the DJI D-Gamut and DJI D-Log choices in the CST input drop-downs are intended for D-Log M, since it isn't a true log format.

Any thoughts?

The only thing about using LUTs is that you can only ever arrive at Rec 709 color space. Rec 709 is the most common color space currently for HDTV, but it’s a very limited color space similar to sRGB. Using a color Transform node in Resolve you can bring your footage into a bigger color world and you’ll be amazed by the increased dynamic range and colors. I usually work in DaVinci Wide Gamut and then I can output Rec 2020 in HDR for YouTube or Vimeo. Most modern phones will display HDR now. Here’s a vertical video I did in HDR last week for Instagram if you are interested.

 

[JavaJack]

The only thing about using LUTs is that you can only ever arrive at Rec 709 color space. Rec 709 is the most common color space currently for HDTV, but it’s a very limited color space similar to sRGB. Using a color Transform node in Resolve you can bring your footage into a bigger color world and you’ll be amazed by the increased dynamic range and colors. I usually work in DaVinci Wide Gamut and then I can output Rec 2020 in HDR for YouTube or Vimeo. Most modern phones will display HDR now. Here’s a vertical video I did in HDR last week for Instagram if you are interested.

Sorry was private as I was just testing. This should be public now:

 

[Hands Down]

The only thing about using LUTs is that you can only ever arrive at Rec 709 color space. Rec 709 is the most common color space currently for HDTV, but it’s a very limited color space similar to sRGB. Using a color Transform node in Resolve you can bring your footage into a bigger color world and you’ll be amazed by the increased dynamic range and colors. I usually work in DaVinci Wide Gamut and then I can output Rec 2020 in HDR for YouTube or Vimeo. Most modern phones will display HDR now. Here’s a vertical video I did in HDR last week for Instagram if you are interested.

Wow, I watched your video on a recent MacBook with XDR display and the colors were jumping out of the screen! Nice work. I'm going to give this a try.

Does YouTube automatically transcode a version of the video for SDR displays? Or if someone with an SDR display clicks on the video, what happens?

 

[JavaJack]

Wow, I watched your video on a recent MacBook with XDR display and the colors were jumping out of the screen! Nice work. I'm going to give this a try.

Does YouTube automatically transcode a version of the video for SDR displays? Or if someone with an SDR display clicks on the video, what happens?

Yes, YouTube does what’s called tone mapping to SDR so it will look right on a screen that does not have an HDR display. Take a look at YouTube’s upload requirements. It can be a little tricky. You must do the right colour space and transfer function for HDR. I’m a certified Dolby colorist so it’s easy for me to figure out. You must use HDR 10 for your metadata on YouTube. If you can’t figure it out ask and I’ll try and help. Your limit for luminance is 1000 nit which is what I used here. You can see the sun off the water is screaming bright compared to the interface of your computer, right? Normal SDR looks so flat to me now. The sun is mush in SDR

 

[Hands Down]

You can see the sun off the water is screaming bright compared to the interface of your computer, right?

Absolutely. Really even the amber terrain in your video looks pretty bright compared to the interface of my computer, but the sun reflection is over the top! It's almost like the rest of the computer UI is dimmed when the video plays (but of course it's not). Pretty awesome!

I'll see what I can figure out. The YT HDR help doc makes sense to me, more or less, but I suppose it's a matter of getting Resolve set up correctly to work in the wide gamut space, cap at 1000 nits, and make sure I set the export settings correctly to include the right metadata.

The Mini 4 offers both D-Log M and HLG. Do you think one of those is better than the other for capturing HDR footage? Resolve seems to detect the color space profile of HLG as Rec.2100 HLG. From my super quick test yesterday, it seemed like HLG clips wouldn't require a ton of grading, and I can let Resolve's Color Management do the heavy lifting, only tweaking a little bit to taste.

 

[JavaJack]

It sounds like you are putting together your thoughts in the right way for HDR. I use D-Log for for my recordings on Mavic Cine and record to ProRes format so 422 recording and 10 bits of depth. D-Log has a huge color gamut that you cannot take advantage of in Rec 709, plus D-Log recording offers 15 stops of dynamic range. There's a paper from DJI here if you are interested that shows a chromaticity chart that overlays D-Log and Rec 709 so you can see the color you're throwing away using a LUT to bring it into Rec 709. https://dl.djicdn.com/downloads/zenmuse+x7/20171010/D-Log_D-Gamut_Whitepaper.pdf I have not shot using HLG as most of my work is for clients who are interested in getting Log footage if they purchase it, but for myself I am very happy with D-Log as a starting point in Davinci Resolve. If you do end up using Davinci Wide Gamut, suggest that you start in. I'll attach a screen grab of what your color settings should look like in Davinci. First you should have the top line in Davinci Color managed. You don't want anything automatic. Next scroll down the list to custom. This opens up every color world possible. The input color space can be set to D-Log if you are only using footage from your DJI Mini, and this will apply the correct input color transform to your footage as you bring it into the project. In the media room when in Davinci Wide Gamut work space, you can select any piece of footage and assign the correct input color transform if Davinci doesn't apply it correctly. In other words you may have sRGB graphics created on a computer, you might have Sony footage, as I do in this screen grab, that is S-Gamut3 Slog3 Cine. I'll add another screen grab. This input color space assigns the correct color input to convert your footage into the Davinci Wide Gamut color space. This is not a LUT but an Input Color Transform. Almost all LUTs result in footage being dumbed down to Rec 709, just to reiterate that point. Back on the color settings, select Davinci WG as your color space, timeline luminance of 1000 nit and output of Rec 2020 and ST2084 1000 nits. ST 2084 is the transfer function that stretches out all highlight information beyond the base 100 nits of standard displays or broadcast television to 1000 nits. This is how HDR is achieved, whether HDR 10 or Dolby Vision. You need to output Rec 2020 as your primary color to match up with YouTubes upload requirements for HDR. I would output as H265 and change the main 10 to 4:2:2 10 and make sure you select embedded metadata and export metadata at the top of the output module. One thing I forgot was that in the master settings in Davinci turn on the tick box for HDR metadata. On the color page select HDR 10 metadata as Youtube doesn't support Dolby Vision. That's all I can think of for now. Oh set you scope style to HDR in the upper right corner. This will then display a scope that shows 100 nits all the way up to 1000 nits or the Dolby future potential of 10,000 nits. You'll want to contain your brightest levels to 1000 nit to avoid clipping in HDR.

 

[JavaJack]

It sounds like you are putting together your thoughts in the right way for HDR. I use D-Log for for my recordings on Mavic Cine and record to ProRes format so 422 recording and 10 bits of depth. D-Log has a huge color gamut that you cannot take advantage of in Rec 709, plus D-Log recording offers 15 stops of dynamic range. There's a paper from DJI here if you are interested that shows a chromaticity chart that overlays D-Log and Rec 709 so you can see the color you're throwing away using a LUT to bring it into Rec 709. https://dl.djicdn.com/downloads/zenmuse+x7/20171010/D-Log_D-Gamut_Whitepaper.pdf I have not shot using HLG as most of my work is for clients who are interested in getting Log footage if they purchase it, but for myself I am very happy with D-Log as a starting point in Davinci Resolve. If you do end up using Davinci Wide Gamut, suggest that you start in. I'll attach a screen grab of what your color settings should look like in Davinci. First you should have the top line in Davinci Color managed. You don't want anything automatic. Next scroll down the list to custom. This opens up every color world possible. The input color space can be set to D-Log if you are only using footage from your DJI Mini, and this will apply the correct input color transform to your footage as you bring it into the project. In the media room when in Davinci Wide Gamut work space, you can select any piece of footage and assign the correct input color transform if Davinci doesn't apply it correctly. In other words you may have sRGB graphics created on a computer, you might have Sony footage, as I do in this screen grab, that is S-Gamut3 Slog3 Cine. I'll add another screen grab. This input color space assigns the correct color input to convert your footage into the Davinci Wide Gamut color space. This is not a LUT but an Input Color Transform. Almost all LUTs result in footage being dumbed down to Rec 709, just to reiterate that point. Back on the color settings, select Davinci WG as your color space, timeline luminance of 1000 nit and output of Rec 2020 and ST2084 1000 nits. ST 2084 is the transfer function that stretches out all highlight information beyond the base 100 nits of standard displays or broadcast television to 1000 nits. This is how HDR is achieved, whether HDR 10 or Dolby Vision. You need to output Rec 2020 as your primary color to match up with YouTubes upload requirements for HDR. I would output as H265 and change the main 10 to 4:2:2 10 and make sure you select embedded metadata and export metadata at the top of the output module. One thing I forgot was that in the master settings in Davinci turn on the tick box for HDR metadata. On the color page select HDR 10 metadata as Youtube doesn't support Dolby Vision. That's all I can think of for now. Oh set you scope style to HDR in the upper right corner. This will then display a scope that shows 100 nits all the way up to 1000 nits or the Dolby future potential of 10,000 nits. You'll want to contain your brightest levels to 1000 nit to avoid clipping in HDR.

One other thing, go to user prefs in the upper left and make sure your monitors are set to high quality and Mac color profile if you are on a Mac with the new P3 display. When you hit command F in the edit room or color room you'll get full screen display in HDR this way. Shift-F keeps some of the Resolve interface in the display area.

 

[Hands Down]

One other thing, go to user prefs in the upper left and make sure your monitors are set to high quality and Mac color profile if you are on a Mac with the new P3 display. When you hit command F in the edit room or color room you'll get full screen display in HDR this way. Shift-F keeps some of the Resolve interface in the display area.

Thanks very much for taking the time to provide all of this detail @JavaJack! This is tremendously helpful. There are a quite a few different settings in different places - not very easy for a rookie to HDR to get them all right! I'll have a go at this and see how far I can get. Will let you know how it goes.

 

[JavaJack]

Yes, Davinci is a bit of a bear for settings. Hopefully this gives you enough to go on. If you produce something 4K that's a minute or more long, you'll think it's failed on Youtube, but don't give up hope, it takes 3-4 hours for their servers to process the HDR metadata. You'll look back and refresh it in a few hours and voila, HDR, so don't give up hope. Start by posting something 5 seconds long so you get more immediate results.

 

[Hands Down]

Thanks, that's a great tip @JavaJack. It would be a bummer to wait 3-4 hours just to find out it didn't work!

 

[Hands Down]

Yay! I think it worked! The footage here is nothing special, but it's what I have at the moment. I wanted something that includes the sun. This was shot in HLG on the Mini 4. I didn't do any color grading - just let color management do its thing.

Does this look roughly right? Thanks again @JavaJack! I don't think that I'd have gotten here without your help.

 

[guitars555]

Yes, Davinci is a bit of a bear for settings. Hopefully this gives you enough to go on. If you produce something 4K that's a minute or more long, you'll think it's failed on Youtube, but don't give up hope, it takes 3-4 hours for their servers to process the HDR metadata. You'll look back and refresh it in a few hours and voila, HDR, so don't give up hope. Start by posting something 5 seconds long so you get more immediate results.

JavaJack this thread is a lifesaver for me. I use CST in DR and couldn’t figure out what color space to use with D-Log-M. I will be trying your advice. I have one question- your video says “for Instagram”. - do the HDR setting also work on IG?

 

[Horfun]

It sounds like you are putting together your thoughts in the right way for HDR. I use D-Log for for my recordings on Mavic Cine and record to ProRes format so 422 recording and 10 bits of depth. D-Log has a huge color gamut that you cannot take advantage of in Rec 709, plus D-Log recording offers 15 stops of dynamic range. There's a paper from DJI here if you are interested that shows a chromaticity chart that overlays D-Log and Rec 709 so you can see the color you're throwing away using a LUT to bring it into Rec 709. https://dl.djicdn.com/downloads/zenmuse+x7/20171010/D-Log_D-Gamut_Whitepaper.pdf I have not shot using HLG as most of my work is for clients who are interested in getting Log footage if they purchase it, but for myself I am very happy with D-Log as a starting point in Davinci Resolve. If you do end up using Davinci Wide Gamut, suggest that you start in. I'll attach a screen grab of what your color settings should look like in Davinci. First you should have the top line in Davinci Color managed. You don't want anything automatic. Next scroll down the list to custom. This opens up every color world possible. The input color space can be set to D-Log if you are only using footage from your DJI Mini, and this will apply the correct input color transform to your footage as you bring it into the project. In the media room when in Davinci Wide Gamut work space, you can select any piece of footage and assign the correct input color transform if Davinci doesn't apply it correctly. In other words you may have sRGB graphics created on a computer, you might have Sony footage, as I do in this screen grab, that is S-Gamut3 Slog3 Cine. I'll add another screen grab. This input color space assigns the correct color input to convert your footage into the Davinci Wide Gamut color space. This is not a LUT but an Input Color Transform. Almost all LUTs result in footage being dumbed down to Rec 709, just to reiterate that point. Back on the color settings, select Davinci WG as your color space, timeline luminance of 1000 nit and output of Rec 2020 and ST2084 1000 nits. ST 2084 is the transfer function that stretches out all highlight information beyond the base 100 nits of standard displays or broadcast television to 1000 nits. This is how HDR is achieved, whether HDR 10 or Dolby Vision. You need to output Rec 2020 as your primary color to match up with YouTubes upload requirements for HDR. I would output as H265 and change the main 10 to 4:2:2 10 and make sure you select embedded metadata and export metadata at the top of the output module. One thing I forgot was that in the master settings in Davinci turn on the tick box for HDR metadata. On the color page select HDR 10 metadata as Youtube doesn't support Dolby Vision. That's all I can think of for now. Oh set you scope style to HDR in the upper right corner. This will then display a scope that shows 100 nits all the way up to 1000 nits or the Dolby future potential of 10,000 nits. You'll want to contain your brightest levels to 1000 nit to avoid clipping in HDR.

@JavaJack thank you for the suggestions! Will you kindly clarify few settings?
- 203 Nit Support checkbox is unchecked - was it intentional? with the recommended mapping 100 nit will become 203 nit which is in line with HDR recommendations to leave higher brightness for peaks
- Use Inverse DRT for SDR is checked but will Davinci consider D-log M as SDR? According to the documentation it will push 100 Nit level to max, which seems too extreme in most situations. Do we need this settings ON in our workflow?

 

[JavaJack]

@JavaJack thank you for the suggestions! Will you kindly clarify few settings?
- 203 Nit Support checkbox is unchecked - was it intentional? with the recommended mapping 100 nit will become 203 nit which is in line with HDR recommendations to leave higher brightness for peaks
- Use Inverse DRT for SDR is checked but will Davinci consider D-log M as SDR? According to the documentation it will push 100 Nit level to max, which seems too extreme in most situations. Do we need this settings ON in our workflow?

These are good questions. I would not select the 203 nit checkbox unless I had SDR material in a timeline that I wanted to uprez to HDR. This project is Davinci Wide Gamut and the material coming into the project is definitely HDR being D-Log. Davinci would not consider this footage SDR. If you got to your media and select a clip and right click and scroll down to input color space, you will see that Davinci recognizes the footage as DJI D-Log/D-Gamut and definitely not SDR or it would be flagged as Rec 709. If you look at the LUT input, there is no LUT involved. Resolve is inputting all the goodness of this color space. If you select the 203 nit checkbox you will be making the HDR material unusually bright. I just tried it on an HDR project and it looked terrible and my highlights began clipping at 1000 nit instead of being safely within the 1000 nit ceiling. The inverse DRT for SDR is on by default even in an HDR project. I could turn it off and it would make no difference to the HDR project. You can test this by opening your color settings in an HDR project, turning this on or off, but instead of closing the settings panel with save, hold down the option key and select save and you will see any change to the footage without closing the panel.

 

[Horfun]

These are good questions. I would not select the 203 nit checkbox unless I had SDR material in a timeline that I wanted to uprez to HDR. This project is Davinci Wide Gamut and the material coming into the project is definitely HDR being D-Log. Davinci would not consider this footage SDR. If you got to your media and select a clip and right click and scroll down to input color space, you will see that Davinci recognizes the footage as DJI D-Log/D-Gamut and definitely not SDR or it would be flagged as Rec 709. If you look at the LUT input, there is no LUT involved. Resolve is inputting all the goodness of this color space. If you select the 203 nit checkbox you will be making the HDR material unusually bright. I just tried it on an HDR project and it looked terrible and my highlights began clipping at 1000 nit instead of being safely within the 1000 nit ceiling. The inverse DRT for SDR is on by default even in an HDR project. I could turn it off and it would make no difference to the HDR project. You can test this by opening your color settings in an HDR project, turning this on or off, but instead of closing the settings panel with save, hold down the option key and select save and you will see any change to the footage without closing the panel.

Thank you! Indeed, Inverse DRT seems to have no effect if DJI Log is selected. I, however noticed one thing - in most of the cases when I select DJI Log and gamma, the effect is too strong and requires lots of secondary adjustments so I go suggested way and select HLG gamma but in some cases with low contrast DJI gamma works better. I can't understand where I am wrong.

And there is another issue - when I grade SDR I monitor saturation via vectroscope so that it does not go beyond primaries and this works just fine. But when grading for HDR the vectroscope is dull no matter how saturated the image is. If anybody can help with HDR saturation monitoring in Davinci Resolve I will appreciate a lot!

 

[JavaJack]

Thank you! Indeed, Inverse DRT seems to have no effect if DJI Log is selected. I, however noticed one thing - in most of the cases when I select DJI Log and gamma, the effect is too strong and requires lots of secondary adjustments so I go suggested way and select HLG gamma but in some cases with low contrast DJI gamma works better. I can't understand where I am wrong.

And there is another issue - when I grade SDR I monitor saturation via vectroscope so that it does not go beyond primaries and this works just fine. But when grading for HDR the vectroscope is dull no matter how saturated the image is. If anybody can help with HDR saturation monitoring in Davinci Resolve I will appreciate a

 

[Horfun]

@JavaJack Looks like you forgot to attach your reply