Gamma Compensation Lut makes Blacklevel shift

I am having the exact same issue. Is there any fix by now?
This is a major problem, that need to be fixed....

I will just chime in with my own 1.5 hours of wtf.  I shot a scene in AVCHD, transcoded the .mts to ProRes 422 .mov and then discovered when playing back the .mov with Quicktime Player that the image would brighten and dim intermittantly.  No apparent logic, and it wasn't a frame-by-frame occurance: there were no darker or lighter frames.  Hmm.  I worked with it in Premiere, where playback showed me no intermittant brightening.  Exports would.  When played back with the Quicktime Player.  More fruitless tweaking with Handbrake and VLC.  Then I added this QT Gamma Compensation LUT and the export (finally) played back correctly. 

I think I've learned something, but not how to determine whether a clip/sequence will trigger this problem.  Do I now need to add this LUT to all of my projects?

To see a "bad" export and a "good" one: https://drive.google.com/drive/folders/13uhbOsQBdkZsbnVAfRFTs8MMWyrYS6SV?usp=sharing

Thanks to everyone who tries to help me and explain the problem. I just don't understand why this Lut works for others on Youtube and not for me 

Here a video to show you what i mean: https://www.youtube.com/watch?v=noFlexiSJxo

Well ... yes ... and ... it's still a mess. There's an array of options, with of course ever increasing costs.

On the Macs, with Premiere's "display color management" option checked, you'll get within PrPro a pretty decent representation of your image.It should be fairly close to how it would  appear on a full calibrated/profiled Rec.709 system. Of course, "define fairly close" ... that's the rub, isn't it? You know it's probably mostly usable and that's about it.

The next up in confidence and cost is a probe/puck solution like the Xrite i1 Display Pro to provide a calibrated ICC profile for Rec.709 for the OS to use. That can give a bit more assurance that the image you see is correct. I'm comfortable with using this on a PC, and am told it also works with the Mac systems as well.

This will cost around $260USD for the Pro, and $300USD for the Pro Plus. The pro is probably entirely adequate for your current needs.

I work with and produce training materails for colorists on a daily basis. So I went a step farther ... after calibrating with the i1Display Pro Plus puck/software, I used another software combination to run a profile. A profile is created from sending test patches to the monitor (like during calibration) and evaluating the tested results to produce a series of graphs showing the current output of the monitor. And can give you very tight information on where your monitor succeeds ... and also, where it fails.

I used the free version of Lightspace (from lightillusion.com) combined with my i1 puck, and Lightspace combined with Resolve as the "patch generator" worked to give me a full profile. After doing so, I tweaked my settings for doing another calibration in the i1 Display Pro software, then ran another profile. Finally getting a profile that matched what colorist's require, I then did a short test export of a few clips and a color bar from PrPro, and sent it to a couple colorists for checking on their highly calibrated/profiled gear with their spendy Flanders monitors. "Good to go" was the response.

However, if I was going to actually do any broadcast, I would first go to the next level up.

This would use a break-out device to get the signal directly from PrPro without the OS or your GPU interfering. As say a Decklink card from BlackMagic, or one of the cards or external boxes from AJA. Such a device would need to be able to hold a calibration LUT for the monitor. I would use a paid version of ColourSpace (the updated Lightspace) to calibrate the monitor and generate a LUT to control the image between the computer and the monitor, and park that LUT in the breakout device so that I know that the monitor is within specs.

This would be $400USD to a couple thousand for the breakout device/LUT box, and something around $770USD for ColourSpace. If you're going that far, going all the way and getting a full-on broadcast standard Grade 1 Reference monitor would be wise, but that's another $5,000 to $10,000USD.

None of this will solve the Mac color management issues/variance from the rest of the world. It would just mean you'd be more confident of the "properness" of your media within Rec.709 and the vast majority of systems out there. I do know some colorists who for say web work try to hit a "between point" ... so their grade is a bit dark and contrastly/saturated for full-on Rec.709 but not quite as light/low-saturated in the Mac as otherwise.

It's frequently all about finding the compromises you can live with.

Neil

Will the method in the video below work?  

That LUT is there for Mac users dealing with the unfortunately unique color management practices of ColorSync on the Macs. It is not well used on media that will be seen across platforms.

Within a Mac, Colorsync does two things wrong in displaying Rec.709 media.

First, it doesn't use the normal spec broadcast standard of gamma 2.4 (semi-darkened room) or 2.2 for bright-room viewing. It applies what they call "sRGB gamma" ... which no one knows what that is ... and from reverse-engineering has been measured at between 1.95 and 1.96.

Second, it only applies the first of the two required transforms. Rec.709 standards require both a scene and a display transform, ColorSync applies the scene but not the display transform.

PrPro is built to run totally b-cast Rec.709 standards. So when working in PrPro on a Mac, you need to check the display color management option in the preferences, which tells PrPro that you're not on a properly specced b-cast monitor. It then looks at the monitor ICC profile, and remaps the image to show as close as possible to a correct Rec.709 image.

Of course, PrPro has no effect on Colorsync, so outside of PrPro, your clip will look as ColorSync tells apps to show it. For "color managed apps", that work under Colorsync, that Rec.709 image will be wrong.

There are a couple players (VLC might be one, I'm not sure) I'm told that ignore ColorSync and actually display a Rec.709 image as correct as you can get on a Mac.

Applying that "gamma correction LUT" is an attempt to make ColorSync display the file correctly on a Mac, that's all. You must understand that if you apply that LUT, and send the file to anyone not on a Mac, it will be way too dark, contrasty, and over-saturated.

So when you upload a file with that LUT applied to Youtube for example, on any non-Mac device it will be dark, contrasty, and over-saturated.

Unfortunately there is no way around that divide between the Mac OS/Colorsync and the rest of the world. No pro colorist can manage it either ... and I work with and for colorists daily.

But then, every device and viewing situation out there will always show your file differently than you see it. The folks doing color for Major Motion Pictures even have to accept this caveat. No one, in any theater, will ever see exactly what their high-end reference monitor or theater projecction setup showed.

The colorists working streaming and broadcast shows have exactly the same issue. And can only do what colorists do: work on a properly calibrated/profiled system and then let it go.

When it goes out "Into the Wild" ... you have no control.

Neil