Cinelog - True logspace conversion for DNG and CinemaDNG footage

Started by Andy600, January 24, 2014, 06:05:11 PM

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Andy600

Is it still crushed without using the lut? RCM is designed so that you don't need to use luts.

If the lut is a 'look' and includes a built-in display transfer function (likely) you would need to negate this by adding the inverse of it's transfer function or use the tools (contrast, curves, LGG etc) to balance the post-lut image.   

Try bypassing the lut and switch back to DaVinci YRGB (not RCM). Disable the 'use separate colorspace and gamma' and set to 'Linear'. Now add the Color Management plugin on the 5D footage and set it to:

Input: use timeline / use timeline
Output: Arri Alexa V3 / Arri LogC

... how does this match the Alexa footage in terms of gamma? (looks flatter than the Alexa right!?) - so try Cineon instead of Log-C which should bring the gamma closer to Alexa footage. You'll need to play with 5D3 footage exposure offset to place middle gray at roughly the same level as the Alexa shots and then balance black level and diffuse white level at close to the same IRE levels as the Alexa shots - ideally there will be some sort of reference chart captured on both cameras and everything will be exposed properly but if not you'll need to do it by eye on 2 similar shots. Skin can be used as a very rough guide for middle gray if there is no better alternative.

Then apply the lut to a track node so it affects all footage on the timeline. How does it look?

You will not get an exact color match between the 2 cameras (the 5D3 raw footage is not color calibrated) so you'll likely need to use 'hue vs hue' and 'hue vs sat' to balance the color. This is where a good reference chart helps immensely.

If a color chart was shot and is supported in Resolve Colormatch you could also try that to map both cameras to a common look...but it rarely works well. 

BTW, if you are using 3D look luts, set lut interpolation to Tetrahedral ;)
Colorist working with Davinci Resolve, Baselight, Nuke, After Effects & Premier Pro. Occasional Sunday afternoon DOP. Developer of Cinelog-C Colorspace Management and LUTs - www.cinelogdcp.com

baldavenger

@Andy600

Now that Resolve includes its own OpenFX API, are you still going ahead with your planned release? I for one think it's still a worthwhile venture, and I'd be happy to purchase (and promote) it once its released. I gather you were pretty close anyway, so now with the easier to implement CUDA and OpenCL based GPU acceleration it should be a more viable prospect?

I know neither C nor C++ (yet) so it might be a while before I'm able to build my own custom plugins, and it would be great if Cinelog could provide a working solution in the meantime.
EOS 5D Mark III | EOS 600D | Canon 24-105mm f4L | Canon 70-200mm f2.8L IS II | Canon 50mm f1.4 | Samyang 14mm T3.1 | Opteka 8mm f3.5

Andy600

Yes! We're still going to release plugins for OFX and After Effects but due to RCM now having separate gamma/gamut abilities and a colorspace plugin we're shifting focus a little. I have a couple of new ideas and we'll probably retain the basic CTL and matrix plugins mainly because DCTL is in Resolve Studio only - DCTL is very cool. The developer info is helping to solve the GPU problems we encountered with OFX so thanks for the hint on LGG!. My own C++ knowledge is very basic so I'm more focused on color science and implementing specific routines (well, I will be after I've released the Cinelog update). I've employed a coder to speed up plugin development so hopefully I'll see a beta soon - I'm eager to try it myself.




Colorist working with Davinci Resolve, Baselight, Nuke, After Effects & Premier Pro. Occasional Sunday afternoon DOP. Developer of Cinelog-C Colorspace Management and LUTs - www.cinelogdcp.com

baldavenger

EOS 5D Mark III | EOS 600D | Canon 24-105mm f4L | Canon 70-200mm f2.8L IS II | Canon 50mm f1.4 | Samyang 14mm T3.1 | Opteka 8mm f3.5

Andy600

@beauchampy - sorry, I messed up  ::) I wrote it from memory. I can't remember V12 doing this either.

Set RCM input to Rec709 (or any colorspace - doesn't matter)  / gamma to Linear (i.e. don't bypass it).

This override's the Camera Raw colorspace settings. If RCM input is bypassed you can still use the Camera Raw colorspaces - but that would get confusing very fast.



DNGs are behaving differently in 12.5 with split RCM. I need to investigate further before I can give a definitive answer.
Colorist working with Davinci Resolve, Baselight, Nuke, After Effects & Premier Pro. Occasional Sunday afternoon DOP. Developer of Cinelog-C Colorspace Management and LUTs - www.cinelogdcp.com

beauchampy

Quote from: Andy600 on April 25, 2016, 05:37:15 PM
@beauchampy - sorry, I messed up  ::) I wrote it from memory. I can't remember V12 doing this either.

Set RCM input to Rec709 (or any colorspace - doesn't matter)  / gamma to Linear (i.e. don't bypass it).

This override's the Camera Raw colorspace settings. If RCM input is bypassed you can still use the Camera Raw colorspaces - but that would get confusing very fast.



DNGs are behaving differently in 12.5 with split RCM. I need to investigate further before I can give a definitive answer.

Thanks for looking into this Andy.

For anyone else looking for a 'quick fix' - Hunters LUT is very close to Alexa Rec709, so I'm using that in conjunction with a LUT made for R709 Alexa.

Andy600



If you setup RCM like this you can render out to Log-C and it's the same settings if you want to add Log-C luts (i.e. on a node). Change ARRI LogC to Cineon Film Log for Cinelog-C.

If you render to LogC or any other colorspace just set the input colorspace and gamma for each imported clip to whatever colorspace you rendered in.

The input colorspace is irrelevant for DNGs but it must be set to Linear gamma. You can also assign colorspace on the timeline for individual shots or use the colorspace plugin.

Colorist working with Davinci Resolve, Baselight, Nuke, After Effects & Premier Pro. Occasional Sunday afternoon DOP. Developer of Cinelog-C Colorspace Management and LUTs - www.cinelogdcp.com

baldavenger

@beauchampy

Would it be possible for you to get hold of a few seconds of LogC from the Arri, where some charts are filmed and also by your 5d mkIII ?

If the scene is metered and suitably recorded, by comparing both sets of footage (after converting to linear light in Resolve) perhaps a clear difference can be pinpointed. I suspect the 5d DNGs will appear darker, as Resolve maps peak white (15000 in the case of 5d) to 1.0, whereas linearised LogC maps diffuse white (@90% scene reflectance) to 1.0 hence why it might appear brighter. It might be possible to match the linearised signals with just the Exposure control, then applying a linear to LogC transform with the new Resolve controls should produce a closer approximation.

No worries if it's not an option, but it would be cool if you could.
EOS 5D Mark III | EOS 600D | Canon 24-105mm f4L | Canon 70-200mm f2.8L IS II | Canon 50mm f1.4 | Samyang 14mm T3.1 | Opteka 8mm f3.5

Andy600

@baldavenger - It sounds like you want to tone map 5D3 linear to match inverse logC?

If you have a gray card ref (~18%) and diffuse white (~90%) you can roughly tone map the linear DNG to LogC middle gray IRE and 90% white. If you do this under the lin2logc transform (on the 5D3 raw shot) you can probably then use the metering in Resolve and match the DNG IRE values to LogC IRE values visually (in logspace) - then remove the lin2logC transform. Peak white will fall where it falls depending on super bright levels the shot. Resolve iluts are useful for this type of thing once you have a reference to build to.

For more accuracy you need a DSC 10 step grayscale chart which comes with a list of theoretical aim values for each chip. You shoot the chart and find the RGB levels for each chip. You might even get away with RGB picker in Resolve to record the shot values but it's better to measure luma in L*a*b colorspace using Matlab or similar. Then you would write a simple lut to map these input/source values to the known aim values (the aim values are normalized 0.0 to 1.0 so the recorded RGB values need to be normalized too).

An XY graph is a good way to build the curve but with so few reference points the lut needs interpolation to smooth things (B-Spline is perfect for this). Then, if we assume the lutted signal is linear (it's not but assume it is) you just add a transfer function like Rec709 or sRGB to correct the gamma for target display. This is the easiest way I know to match camera grayscale tonality in post but it does clamp the signal so it's output referred - however, knowing the mapped linear reference values does make it possible to build a curve fitting function - concatenate this with the Rec709 transfer function and you can then simply go Rec709 to Log-C because the footage is still effectively linear until it's rendered to something else. If it's been rendered to log, add the log to linear transform before the tone mapping and display TF then go Rec709 to Log-C.

I haven't looked at at ARRI Rec709 luts but I bet, if the lut is converted to linear gamma, they map LogC close to DSC aim values. I'll check sometime.
Colorist working with Davinci Resolve, Baselight, Nuke, After Effects & Premier Pro. Occasional Sunday afternoon DOP. Developer of Cinelog-C Colorspace Management and LUTs - www.cinelogdcp.com

baldavenger

@Andy600

Thank you for the detailed explanation. I am indeed interested in matching 5D3 linear to inverse LogC, or more specifically converting the DNGs into true scene linear. Resolve still processes DNGs as display referred, and takes its cue from the black level and white level in the metadata. The white level can be changed (and therefore the part of the signal mapped to 1.0), but it also clips at that point unless Highlight Recovery is enabled.

If there was a standard (i.e linear scale) way of transforming the Raw information into true scene linear, then it would be much easier to make work with other camera sources. As it stands, applying lin2log conversions (such as Cineon or LogC) is a bit pointless in that the signal has already been squeezed because of DNG interpretation. Anyway, it would be handy to put these ideas to the test.
EOS 5D Mark III | EOS 600D | Canon 24-105mm f4L | Canon 70-200mm f2.8L IS II | Canon 50mm f1.4 | Samyang 14mm T3.1 | Opteka 8mm f3.5

DeafEyeJedi

Actually after reading all of this thoroughly twice or so. Wonderful stuff. Even though I wonder does this mean I'll need to adjust my workflow in DR12 accordingly if I were to update to the latest version?
5D3.113 | 5D3.123 | EOSM.203 | 7D.203 | 70D.112 | 100D.101 | EOSM2.* | 50D.109

GutterPump

I'm hoping someone that makes us a little video tutorial showing us news techniques for using Cinelog -C with Davinci Resolve 12.5

It look really interesting and useful


Andy600

Yes, Cinelog-C DCP 2016 will be out soon and it's a free upgrade for current users.

We can now build ACR profiles in any log colorspace, not just Cinelog-C but it's a premium service and not something I envisage most users wanting or needing except maybe where the camera's DR is too much for Cineon i.e. BMD URSA Mini 4.6k.

There will be a smaller update later to Cinelog-C for DaVinci Resolve (aimed at users who can't run V12.5 with RCM) and some additional .DCTL luts for Resolve Studio plus some new looks compatible with both versions.
Colorist working with Davinci Resolve, Baselight, Nuke, After Effects & Premier Pro. Occasional Sunday afternoon DOP. Developer of Cinelog-C Colorspace Management and LUTs - www.cinelogdcp.com

DeafEyeJedi

Thanks for the much anticipated update as it will be worth all the hype that we've been getting ourselves into as of late, right?

Looking forward to it, Andy and please take all the time you need to iron out the quirks. Also let me know if there are any beta testings that I'd be willingly to do for you when necessary.

*edit*

I just recently bit the bullet by going Beta3 w DR12.5 (thanks to @reddeercity for ur support) and assuming that everything has been fine with the current workflow that I use from your site.

Seems to be on my end but sounds like there'll be ways for improvements? The new features/specs especially with the luxurious exporting options. Really nice. Don't forget their new additional 'sliders' for CC.

BM is finally catching up to ACR.
5D3.113 | 5D3.123 | EOSM.203 | 7D.203 | 70D.112 | 100D.101 | EOSM2.* | 50D.109

djkraq

I love Cinelog.  How do we download the new update?  I don't see a link.  It just allows me to buy it again and download it.

edit - NVM.  I now see its not released yet.  13.5 stops of DR?!  Can't wait to test this out. 

ibrahim

Is there a version of cinelog-C for lightroom since I don't use ACR?

How much difference is there in the picture quality (end result) between visionlog and cinelog in Lr after having converted my .MLV to cDNG with raw2cdng?

Is there any better alternative to visionlog than matches cinelog-C?
Canon 5D Mark IIIs | Ronin-M | Zeiss 50mm 1.4 planar | Zeiss 35mm 1.4 distagon  | Zeiss 24mm f2 distagon | Zeiss 85mm f1.4 planar
Dual sound system: Tascam DR-60d MKII | Audio Technica AT899 | Sennheiser MKE 600

dfort

Quote from: Andy600 on June 03, 2016, 01:10:15 PM
Yes, Cinelog-C DCP 2016 will be out soon and it's a free upgrade for current users.

I got the upgrade, Yay! Now I've got to confess that I haven't been using it until today so this is a new installation for me. First thing that threw me off was the installation instructions:

http://www.cinelogdcp.com/cinelog-dcp-2016-installation

QuoteMac OSX installation path

Library/Application Support/Adobe/CameraRaw/CameraProfiles

Well, that would be a system wide installation but it didn't work when I tried it. The correct installation path for the Cinelog-C 2016 Digital Camera Profiles folder is: ~/Library/Application Support/Adobe/CameraRaw/CameraProfiles

So, that got me past the first hurdle. Now I've got to figure out the rest of it.

dfort

Installing the OCIO plugin was also a bit tricky. Following the installation instructions you don't really need to download the spi-vfx but it is necessary to put the Cinelog DCP 2016 folder into /Library/Application Support/OpenColorIO/ if you're on a Mac.

Everything is working great except the LUTs. I tried adding some of the look LUTs via both the Lumetri and the "Apply Color LUT" effect but it keeps coming out way too dark when applied over a LogC clip. Not sure what's going on with that. I is probably something I'm doing wrong because I can't tick the Preserve RGB box under Interpret Footage/Color Management.

Andy600

Thanks for the path info - I'll update it.

The look luts are for Cinelog-C (Cineon), not Log-C and can be applied directly to Cinelog-C footage coming from ACR. Try loading a lut using OCIO, not Lumetri.

If the image is dark see the Exposure adjustment advice in the LUT Bank. There are also several built-in looks under the plugin's Display button.

You can't change interpretation for footage coming from ACR. The profiles are compensated for using 'HDTV Rec.709' workspace and the AE workspace MUST be set to this for the math to work.
Colorist working with Davinci Resolve, Baselight, Nuke, After Effects & Premier Pro. Occasional Sunday afternoon DOP. Developer of Cinelog-C Colorspace Management and LUTs - www.cinelogdcp.com

vstrglv

Thank you very much for update! But how can I get  "Cinelog_DCP_2016.zip", could not  find on http://www.cinelogdcp.com.?
.
Canon 5D3,1.1.3; Canon EOS M,202,  CF-SanDisk Extreme PRO,160MB/s, 256GB, SD-SanDisk Extreme Pro, 170MB/s, 128GB.

dfort

Quote from: Andy600 on July 11, 2016, 12:05:32 PM
...
The look luts are for Cinelog-C (Cineon), not Log-C and can be applied directly to Cinelog-C footage coming from ACR...

My bad, I'm applying Cinelog-C to the cdng files with ACR:


And I've got the Cinelog DCP 2016 package working fine with the OpenColorIO plugin:


So now to install the look luts that I downloaded from the lut library:


You are saying:

Quote from: Andy600 on July 11, 2016, 12:05:32 PM
...Try loading a lut using OCIO, not Lumetri...

Which I take it isn't as simple as just dropping the luts into the Cinelog DCP 2016/luts folder:


This will require either modifying existing config.ocio file or creating a new one that contains just the luts that I want to work with. Problem is, to write a valid config.ocio isn't a trivial task. A quick read of the OpenColorIO config syntax is humbling for this mere mortal filmmaker and trying to modify the config.ocio for the Cinelog DCP 2016 package is not making things any easier. For example as far as I can determine these are the pieces that are needed to activate the Cinelog Film Look 1 shown on my screenshot:

displays:
...
  Rec709:
...
    - !<View> {name: Cinelog Film Look 1, colorspace: Cinelog-C, looks: print1fc}
...
looks:
  - !<Look>
    name: print1fc
    process_space: Cinelog-C
    transform: !<GroupTransform>
      children:
        - !<FileTransform> {src: Cinelog_Film_01.cube, interpolation: tetrahedral}
        - !<CDLTransform> {slope: [1.2, 1.2, 1.2]}
        - !<CDLTransform> {offset: [0.03, 0.03, 0.03], direction: inverse}
...


So I'm lost, how exactly do I load your custom luts using OCIO?

I think I got my head wrapped around the other issues you mentioned:

Quote from: Andy600 on July 11, 2016, 12:05:32 PM
...If the image is dark see the Exposure adjustment advice in the LUT Bank. There are also several built-in looks under the plugin's Display button.

You can't change interpretation for footage coming from ACR. The profiles are compensated for using 'HDTV Rec.709' workspace and the AE workspace MUST be set to this for the math to work.

I've been careful to follow the advice in the Exposure Compensation The Right Way! section of your documentation.

Andy600

I'm building a separate 'looks' config specifically for previous look luts but it won't be ready for a week or so.

Until then, you can easily load luts (several formats) by clicking the Configuration dropdown in the OCIO plugin and select 'custom'. This will open a browser window. Find a lut, set interpolation to tetrahedral for 3D luts, Linear for 1D luts (Cinelog looks are 3D) and you're good to go.

If applying to regular footage (not from ACR) first convert the footage to Cinelog-C then use a second instance of the plugin to load a lut.
Colorist working with Davinci Resolve, Baselight, Nuke, After Effects & Premier Pro. Occasional Sunday afternoon DOP. Developer of Cinelog-C Colorspace Management and LUTs - www.cinelogdcp.com

vstrglv

But how  to update Cinelog_DCP to Cinelog_DCP_2016. Have i to buy DCP again?
Canon 5D3,1.1.3; Canon EOS M,202,  CF-SanDisk Extreme PRO,160MB/s, 256GB, SD-SanDisk Extreme Pro, 170MB/s, 128GB.

Andy600

@vstrglv - No you don't need to purchase it again. I've PM'd you.
Colorist working with Davinci Resolve, Baselight, Nuke, After Effects & Premier Pro. Occasional Sunday afternoon DOP. Developer of Cinelog-C Colorspace Management and LUTs - www.cinelogdcp.com