Cinelog - True logspace conversion for DNG and CinemaDNG footage

[timbytheriver]

@Andy600 Ah! Thanks. I think I see! So if I buy the ACR profile only it'll get me into Cinelog only. But if I buy the Resolve pack I can get it into Cinelog-C (near Alexa) via Resolve? Then grade in whatever when I render out …

@dmk Thanks! I did miss something!

[Andy600]

@timbytherive - Yes. The ACR version is not Cinelog-C (yet). We have still to work out a good DCP conversion to BMD colorspace (and then to Cinelog-C/Cineon) and embed this as a HSV table and tone curve in a camera specific DCP. This is really not an easy thing to do and we're still developing the backend conversion scripting. We have all the parts so it's just a matter of time.

Resolve 11 is IMO at the level of ACR now (in terms of debayer, highlight and shadow recovery, detail etc). I'm getting consistently good results with Cinelog-C in Resolve 11 and you'll see over the next few weeks what it can achieve. I'll also get hold of Impulz at some point and demo what can be done when the 2 packs are combined.

[timbytheriver]

@Andy600 Thanks for the honest answers!

I ditched Resolve over a year ago because I have a modest specced machine, but I guess I need to take a look again if it's improved that much!

Thanks again.

[Andy600]

I've been an Adobe user for years but apart from AE for VFX I rarely touch their software now. Resolve ticks all the boxes for me personally.

BTW, when we talk about Alexa color there is really only way to get it and that is to shoot on an Alexa. What we're trying to do is emulate some of the aesthetics of how the Alexa sees color, especially skin tones and color separation and apply this to raw footage from Canon DSLR's and other raw shooting cams. The Alexa also controls saturation in a clever way. It's relevant to ISO and exposure but you can emulate this part quite well in Resolve using the sat vs lum curve.

[timbytheriver]

Hear you about the Alexa. When I said Alexa I meant [poor-man's] Alexa. 

Would it be cheeky for me to post a [troublesome] sample DNG file and ask you to see what can be achieved by the ACR Cinelog conversion alone?

[Andy600]

Hear you about the Alexa. When I said Alexa I meant [poor-man's] Alexa. 

Would it be cheeky for me to post a [troublesome] sample DNG file and ask you to see what can be achieved by the ACR Cinelog conversion alone?

Poor-man's Alexa = anything shot on a camera other than the Arri Alexa 

re: DNG - no problem. Can you email me a download link via the contact form (website link in my sig)

[timbytheriver]

Can you email me a download link via the contact form

Have just done so. Thank you again.

Tim

[Andy600]

Have just done so. Thank you again.

Tim

Whoa! that's trippy 

I'll see what can be done and post it back to you.

[QuickHitRecord]

I am very intrigued by this product, but I have skimmed this entire thread and unless I have missed something, I haven't seen a side-by-side comparison of how Cinelog differs from VisionLog. Even screen grabs of Resolve (with scopes) of VisionLog and then Cinelog applied to the same clip would be helpful. Even better: screen grabs of the same white-balanced clip with each LOG applied, and then with the same Alexa-emulating LUT applied. If this has been posted and I have missed it, please refer me to the URL.

[Andy600]

@QuickHitRecord - You can't use the Cinelog-C luts with VisionLog because the source colorspace would be totally different but you can use VisionColor's Impulz luts (Cineon/Log input) with Cinelog-C. The source colorspace needs to be Cinelog-C for our gamut luts to work but Cinelog-C is Cineon log gamma too, so will work with any lut or profile that expects a true log/Cineon input. It's not just about the gamma or log curve, it's about RGB primaries, saturation, hue, luminance and a multitude of other things.

If you look at the BMD Film to VisionLog lut on scopes using either the SMPTE colorbars or a linear ramp there are big colorshifts and an uneven gamma curve. I presume this was done to counter something in the BMD film colorspace to get to the same look as their ACR version!? The BMD film gamma component is now known (there are luts for it) but we also have a model of the actual BMD colorspace and the colorshift does not actually happen, hence it does not need any correction unless you are targeting a bespoke colorspace, which VisionLog is. My guess is that the Visionlog lut is a Matchlight generated lut (a lut ripping app from LightIllusion) and there is no mathematical way to fully revert it without another Matchlight generated lut (and every one of these conversions degrades the signal a little). This is why we do the most important transform with math only and why Cinelog-C gamma conforms to measurable standards (i.e. it's the same industry standard Cineon formula found in OpenColorIO, CTL etc).

I'm not knocking VisionLog because a) it's free and b) you can likely get good results with some work or their other luts, but you have to understand it's limitations and drawbacks (i.e. invertibility, colorshifts and compatibility with standards).  Cinelog-C on the other hand conforms to open standards for gamma transforms and only the color components are unique. I'll post some examples later

[dmk]

OK, I'm actually very confused... just to compare, I opened up one of my DNGs and it inherently looked much better than what I was getting for starters in resolve (both via Resolve's native CinemaDNG and using Cinelog)

Here is the ACR, set white balance to 6500 and tint = 0



Here is the Resolve, set white balance to 6500 and tint = 0 (and BMD Film 4K)
LUT #1 = [INPUT] BMD Film 4K -> Cinelog-C
LUT #2 = [MONITOR] Cinelog-C -> Rec 409



To my eye, it's not a matter of just bumping the exposure, when I do that the Resolve one doesn't look as good as the Adobe

So back at square 1, recut the film in Adobe? Aye... what's even the best process for that to utilize ACR, assuming disk space isn't an issue? Grade in After Effects with Synthetic Aperture?

EDIT: And just for fun, here's a DNG from around the same timestamp exported with same basic settings direct from Premiere... yet another difference!

[Andy600]

@dmk - You need to adjust your WB in Resolve and not use a default settings because it's expecting footage shot on a Blackmagic Camera which have different XYZ matrices. It will not match ACR settings. Push up exposure in Resolve to around 0.75 or maybe a little more and add a little Y channel sharpening (i.e. add a node, set it to YUV colorspace, switching off channels 2 and 3 and then add some negative blur to around -0.47). You could also add a little midtone detail (in the Colormatch panel).

What profile/LUT combination did you use to get to that point in ACR?

[dmk]

Yeah, but it doesn't quite look as good when bumping the exposure...

Didn't use any profile or LUT in ACR

[Andy600]

You won't get a perfect match with ACR this way (that's not what Cinelog-C is intended for) but this looks like a simple gamma/scaling issue and it's probably to do with the difference between video and data levels. Can you send me this image and I'll work out the best settings for you to get close in Resolve?

Default ACR output is a film curve with 2.2 gamma. Rec709 is a little different. Try this combination: BMD Film 4K to Cinelog-C + ProPhoto gamut lut + sRGB output lut (you will have to add some saturation). BTW, we have some luts coming to the Lut Bank that replicate Canon Picture Styles and ACR default output but using Resolve (these are for users who don't need/want to convert to log first).

Remember, ACR does not output a true Rec709 signal on it's own. It's a photo enhancement and usually looks wrong on a TV screen.

You are definitely using a profile in ACR. If you didn't select one it will use the default profile.

[Andy600]

Re: the differences between Resolve and PP, AE, FCp etc etc - it's a nightmare familiar to colorists everywhere. That's why it's best to stick with known (SMPTE) standards. We can work out the scaling differences and make something to bridge different apps to fix gamma mismatch etc. It's like the gamma shift you get with H.264 - it's different across several apps because developers don't always stick to standards or they interpret them differently.

You might have to output at Video levels from Resolve or set you workspace to linear gamma (i.e. in After Effects) but it's wholly dependent on the app you are going to work in and the source signal/gamma. Don't fret, there is a solution for everything

[dmk]

Cool, thanks for taking a look. Here's the file (maybe a frame or two off, but just about right):

http://we.tl/BLiNanPbhn

You are right, it was using the embedded profile... probably the technicolor one from when I was shooting h.264

For what it's worth, speedgrade 2014 rendered it almost totally black upon initial open, lol

So so far the only app that *really* gives me what I'd expect is After Effects, but then you can't grade the DNG directly (actually- what happens if you just adjust exposure and white balance in ACR that way, and then throw Synthetic Aperture/Color Finese on top... is that a high quality workflow, even if it means having to write down timecodes by hand to match an EDL? Last time I tried something like that was ages ago... and Color Finese didn't exactly reflect the ACR settings, had to toggle back and forth)

Gotta run, will be back later

[dmk]

Re: the differences between Resolve and PP, AE, FCp etc etc - it's a nightmare familiar to colorists everywhere. That's why it's best to stick with known (SMPTE) standards. We can work out the scaling differences and make something to bridge different apps to fix gamma mismatch etc. It's like the gamma shift you get with H.264 - it's different across several apps because developers don't always stick to standards or they interpret them differently.

You might have to output at Video levels from Resolve or set you workspace to linear gamma (i.e. in After Effects) but it's wholly dependent on the app you are going to work in and the source signal/gamma. Don't fret, there is a solution for everything

I think what might work really well is when you can get from ACR(DNG)->Resolve, and apply a LUT to see exactly what it looked like in ACR originally

The only piece that's missing for that is ACR->Cinelog-C right? Once you've got that, then it's in a standard that should look the same everywhere- and nothing really gets lost in the above workflow (assuming 10-bit intermediate)?

[Andy600]

Cool, thanks for taking a look. Here's the file (maybe a frame or two off, but just about right):

http://we.tl/BLiNanPbhn

You are right, it was using the embedded profile... probably the technicolor one from when I was shooting h.264

For what it's worth, speedgrade 2014 rendered it almost totally black upon initial open, lol

So so far the only app that *really* gives me what I'd expect is After Effects, but then you can't grade the DNG directly (actually- what happens if you just adjust exposure and white balance in ACR that way, and then throw Synthetic Aperture/Color Finese on top... is that a high quality workflow, even if it means having to write down timecodes by hand to match an EDL? Last time I tried something like that was ages ago... and Color Finese didn't exactly reflect the ACR settings, had to toggle back and forth)

Gotta run, will be back later

Technicolor Cinestyle isn't a DCP profile. They are different things. ACR will likely have defaulted to ACR 4.6 or later but it could also be set to default to something else (check the ACR profile slot where you would normally select VisionLog or Cinelog). ACR default is RIMM/ProPhoto RGB. We can match this exactly if needed

re: Speedgrade - Black = normal, it needs matrices and gamma settings added to work with DNG footage.

re: ACR, color finesses etc - It will work ok but will be a lot slower because you are having to debayer every frame (unless you have rendered to intermediate or proxy video first). Everything happens in floating point so you won't ruin your footage but remember to check if a lut clamps the output - if it does then you need grade under it (i.e. before the lut).

Cinelog-C, being Cineon gamma has measurable black and white points that will be accurate in Color Finesse, infact I'm going to look at it in a moment to see if the indicated levels/gamma shift is what I predicted. If so it's an easy fix with a couple of workspace settings.

[Andy600]

I think what might work really well is when you can get from ACR(DNG)->Resolve, and apply a LUT to see exactly what it looked like in ACR originally

The only piece that's missing for that is ACR->Cinelog-C right? Once you've got that, then it's in a standard that should look the same everywhere- and nothing really gets lost in the above workflow (assuming 10-bit intermediate)?

Yes, there will be an ACR version that matches Resolve (or as close as we can get within the confines of the Adobe DNG/DCP HSV profile architecture). We will also do something to match ACR output but this should only be seen as a 'look'.

[dmk]

I guess what's really throwing me off is the BMD Film setting making the CDNG so dark... needing to +1 the exposure just feels like too drastic an adjustment. Am I crazy?

Would it be better to use ACR and the current version of Cinelog to render out stills (or DNxHD... though there's issues from AE with that...), bring that into Resolve and just grade that by hand?

[Andy600]

I guess what's really throwing me off is the BMD Film setting making the CDNG so dark... needing to +1 the exposure just feels like too drastic an adjustment. Am I crazy?

Would it be better to use ACR and the current version of Cinelog to render out stills (or DNxHD... though there's issues from AE with that...), bring that into Resolve and just grade that by hand?

No, that's fairly typical (I think +0.74 exposure was the normalizing mid point offset for the 5D and other Canon cams are around the same). It won't hurt the footage. You're just increasing exposure relative to the BMD film profile. It's all happening in floating point and Cineon log has up to 13.5 F-stops compression in 10bits i.e. plenty of headroom.

I've just rendered your frame in Resolve and will have a look in AE now and get back to you.

here's a few example lut combinations + added a little midtone detail, sharpening and sat (maybe a little too much for some tastes) and subtle vignette. Nothing you can't achieve in 2 mins. I can save them as Resolve Powergrades if you like any of them or want to see the adjustments

Bottom row = Cinelog-C / Cinelog-C + sRGB Monitor Lut / Cinelog-C + Prime Cine RGB + Rec709 output lut

[dmk]

Nice seeing what can be done so quickly. I think these looks lend themselves much more to the sortof action/thriller sort of genre, not so much an old world naturalist vibe... but very good to know that there's a very quick route to that commercially-successful sortof look using your LUTs. Kinda makes me want to shoot something in this genre just to show how easy it is to blow someone's socks off

Understood that it's not limited to that at all either.

Thanks for confirming it's not a big deal to bump up the exposure too, no doubt others might have wondered the same.

For right now, this project, I'm going to try going the AE route and see how it goes. This is such a small piece, and I might give FilmConvert a whirl too.

Thank you for all your help- even if I don't use it for this project, I'm happy with my purchase and looking forward to using it (and Resolve) in the future where it's a better fit (esp. where there's lots of media, intermediaries, deadlines, etc.) Rare that you get such dedicated feedback from the actual developer (for my dayjob- I'm coding mobile apps and web services and things like that, I have a huge appreciation for the technical R&D process and how it can be to need to explain it over and over again)!

Can't wait till the next project and to see all the improvements that have happened in between

Later!

[dmk]

LOL, well, nm... playing around in AE/FilmConvert didn't ultimately get me any better... seems the tools aren't the limitation

Now to reconstruct how in the hell I got to my most favorite setup in Resolve hehe.

Hope my notes help someone avoid making the same mistake I did... do not be fooled by the initial dark levels! As Andy said, there's more than enough there, and you gain nothing but heartache trying to go the AE route...

[Andy600]

Once you match the default ACR output gamma it really shows the color separation

[dmk]

So I had some trouble in Resolve again... not due to Cinelog, just my own troubles getting it where I wanted, matching a reference I had previously. I'm sure I'll have more headache in AE, but going to start there and try again tomorrow.

Hehe... I've got to learn to let it go and move on to the next thing. I'm telling myself I'm not going to spend nearly as much time matching all the other clips as I did just to get this one the way I like.

But it's a good learning exercise anyway

Here's where I ended up, FYI (AE+ACR+FilmConvert... adjusted exposure in ACR and not much in FilmConvert.

EDIT: Hah, nevermind what was there before... had bad camera settings.... here's the latest: