Green / Magenta shift in Sony S-Log clips

The issue is weird: I experience a color shift from one frame to the other, from a green tone to a majenta tone.

I'm not even sure if it's a FCPX problem or Sony files problem.

These are the details:
I regularly imported the clips and created the proxy files, clips being Sony A7sII S-Log3 .mp4 files.

I then edited the sequence and created an adjustment layer with LUTility where I applied an LUT and a layer of color correction.

Now, in one library, while working on proxy mode, everything is fine, while in another library I am working on, this issue shows itself even in the media library clips, without any Color Correction on. The problem of course is when it appears in the Optimized/Original mode, and it also shows in the export, which is unacceptable.

It just started happening recently, and I managed a couple of times to eliminate it by just reducing the saturation of the clip. In other occasions it just doesn't make a difference. At times it appears at the beginning and end of a title applied on the timeline, others it doesn't.

This is the difference between one frame and the following one.



I really can't get my head around this but I need to know how to tackle it and fix it asap.

Would it be possible that is has to do with the white balance of the clips? Or the LUT (strange because it also appeared in the media library).

Thanks in advance to anyone who can help me out,
much appreciated,
Jack

Hello Jack, welcome to the forums.

When you start troubleshooting a problem, the first thing you need to do is to simplify things. So let's try to eliminate anything that does not affect the problem:

You say: Now, in one library, while working on proxy mode, everything is fine, while in another library I am working on, this issue shows itself even in the media library clips, without any Color Correction on.

I don't think this issue has anything to do with the Library you are working in, but we have to be sure first. Take a problematic clip from the "bad" Library and copy it into the "good" Library. If the problematic clip also shows the issue in the "good" Library, we can eliminate the Library as a probable cause and we should concentrate on the original media instead. So that's the first thing you need to test, then post back.

- Ronny

Hey Ronny thanks for your reply & the welcoming.

I tried copying the corrupted clip into a library where I had never any issue, and it keeps happening. The clip without any colorgrading still has the issue, and also if I copy and paste on it the exact effects from the other healthy clips in the timeline, both directly onto the clip, or on an adjustment layer placed upon it.


I couldn't find anything related to the issue online before, but now I found this:
discussions.apple.com/thread/4476457?start=0&tstart=0

It hasn't been fully solved as a thing. And I tried to apply Broadcast Safe on as many clips with the issue I could bother to. For some it made it disappear, for others, completely no change.

They say it might be related to third party plugins. (The ones I'm using at the moment on the clips at stake are (LUTility & various LUTs). But I had found the issue even in the media library up left, before any plugin could even be involved.

Deleting all generated library files didn't help either.

What else could I try?

Thanks a lot,
Jack

Hey Jack, thank you for the test. This tells us that there is nothing wrong with your setup or your NLE. It's also not related to any plugins, because you use the same plugins on clips that are fine and on clips that have the issue. So it's obvious that the problem is within the clips themselves.

I have seen that thread, but that solution really only limits the luminance and chrominance of the clips to broadcast standards. It may solve the issue on some clips, because I think the problem has to do with the brightness of the images. There have been many reports about clips shot with Sony FS5 and FS7 showing a strong magenta cast, and someone even created a special LUT to work around this issue: www.hingsberg.com/index.php/2016/02/magentakiller/

You might give this a try, or otherwise reduce luminance and saturation on the clips and do a little magenta subtracting using the Color tool.

- Ronny

I disagree Ronny. The problem is in FCPX because if I look at the clips from the finder, in my actual harddrive folder they are fine.

It's not about a magenta cast. It's about a short sequence of frames flashing between green and pink colors, not an overall layer or look on the totality of the clip. Not only, but as I re-rendered clips or changed values even slightly the frames affected by the flashing change across the clip, so it's definitely related to how FCPX handles the clips.

It strikes me that this issue was made known in 2012 and still there's not a finalized solution to it.

Today, I deleted FxFactory along with the Timecode plugin. And as a deleted render files & re-rendered it stoped having issues totally. Now it came back to a way minor set of clips and it's not even as noticeable as before. Yet, I still believe it is a matter of how FCPX handles the clips, which is goddamn annoying, and totally unreliable.

Please, don't be so quick to draw conclusions deeming the sony files as faulty, FCPX is known to have issues of this kind, we should look at how to solve it once and for all, and not shift the root of the problem to a different agent every time the issue arises.

I believe it involves the relationship between FCPX and the system version on the Mac, as well it's handling third party plug-ins.

Hopfully, FCPX 10.3 won't have this issue again...

Hi Jack,

If you have concluded beyond any doubt that this issue is related to FCP X, there's not much we can do except advise you to file a bug report.

Enjoy the holidays!

- Ronny

Ronny,

This is off-topic - but I just wanted say thank you for all the support and advice you've offered to everyone who visits this forum. You may just have the patience of an angel too.

Happy Holidays,

joe

You might have to tweak the profiles of the camera itself. I owned a Sony A7s mark 2 for a few weeks and I had lots of trouble getting color to look right. For example, people's lips would often be purple. I looked up a lot of stuff on the camera and tried many different things but I could never get the colors to look right, even after color correction/grading. Sad to say I returned the camera and went back to Canon.

That doesn't help you I know. It's odd that it should be doing this on a frame-by-frame basis.

jackleonardo wrote: Would it be possible that is has to do with the white balance of the clips? Or the LUT (strange because it also appeared in the media library).

I've seen this kind of sudden color changes before. Your two screenshots looked familiar. I believe your suspicion above describes the cause. Had this a few years ago. My friend was snorkeling in a lake at sunset with a GoPro, I filmed him and two other divers from the shore with a GH2. The sun was low, and in the shallow water there were a lot of quickly changing gradients from clipping white to pitch black. I just did a normal CC with it, using Premiere CS5.5 and Color Finesse, nothing fancy. Before CC, the image seemingly was composed mainly of the colors bright and dark green, some yellow and cyan (sky under water). All of a sudden, the colors changed psychedelically, purple flashes, bright green flashes on top of a dark blue background. I liked it very much.

jackleonardo wrote: I couldn't find anything related to the issue online before, but now I found this:
discussions.apple.com/thread/4476457?start=0&tstart=0

We all remember these issues. They don't fit your description at all, believe me.

jackleonardo wrote: It hasn't been fully solved as a thing. And I tried to apply Broadcast Safe on as many clips with the issue I could bother to. For some it made it disappear, for others, completely no change.

Check the uncorrected clip with RGB parade. I bet you'll find that everywhere where the problem occurs, one color suddenly clips. It's there from the start. If you normalize or optimize the clip (i.e. through a LUT), you'll seemingly introduce these colors, but it's just an exaggeration/distortion of what was there before.

Try the free Resolve, and don't use LUTs (the best way to quickly de-grade an anyway threadbare data source like Slog3 in 8-bit, LUTs use too few sample points). FCP X is not responsible for this (if I am right with my assumptions), but particularly it's exposure/saturation/color can't deal with such problems very well, mainly because it's hard to define a relation between them. In Resolve, you can apply a node with Luma vs. Hue or Hue vs. Sat curve. See what happens in Resolve.