Getting Red Noise In Black Areas In Videos

[Hecubus114]

EDIT:  I have narrowed this down to a Lumetri problem.  When I switch off my Lumetri FX and export, the problem is gone.  Not a solution though...

A couple times now that I have exported video From Premiere Pro (newest and version previous to that), I am getting red noise in my black areas (inside person's mouth, creases in armpits, etc.).  I have tried exporting straight from Premiere and through Media Encoder, and in different file types, and always get the same result.  The first instance I got around my rendering straight from After Effects (it was a linked comp), but my current project is Premiere only.  Both times the footage had a decent amount of color correction, but the red noise only shows up in the final exported video - all my previews in Premiere look completely normal.  Has anyone experienced this?  There is nothing new about how I am editing or exporting... its the same workflow I have used for years.

System specs:

Mac (27-inch, Late 2012) OS Sierra 10.12.6

3.4 GHz Intel Core i7

NVIDIA GeForce GTX 680MX 2048 MB

[R Neil Haugen]

That is most likely induced by the corrections, as it's easy enough to induce artifacts in color/tonal corrections. It could possibly be from the export process, more likely if you have "Max render depth" or "Max quality" checked in the export dialog.

Screen grabs of the settings in the Lumetri tabs you're changing, and one showing the RGB Parade scope and the Vectorscope YUV would be nice to get a feel for the issue, along with a frame of the export showing the noise/artifacting.

Neil

[chrisa83746927]

also experiencing some red noise when rendering.. screen shot attached post render, and still to show the difference.

[R Neil Haugen]

One addition to my comments ... for the areas you're having issues with the red noise, set your program monitor to 100%, adjust so you're seeing an affected area, and go through the tabs in Lumetri un-checking them and then one by one, check them to turn that one tab on again, and see which work in which tab is the cause.

I've found that some clips, especially 8-bit media with the exposure anything other than perfect, are more likely to artifact than others. The work-around for color work is to break the work into small amounts towards the goal, done by different tools. Say raising the shadows with the Shadow slider in Basic causes an issue. Raise the shadows only a small amount, not enough to see any damage.

Then go to the Curves tab, and work the white or maybe color curves up a very small amount, again as much as you can before it starts artifacting.

Then try the Shadows wheel slider in the Color Wheels tab for another small lift to the shadows.

Working like that, I've been able to get where I needed without having too many problems.

Neil

[Hecubus114]

I will try and get some screenshots up later, but it sounds like as you are describing, if certain sliders get pushed too far, I start getting this problem.  Where blacks are getting clipped it looks like.  The strange thing is that the red noise does NOT appear until I have rendered a video - everything looks fine while editing.  And, if I send a clip to AE and export from there, the problem does not happen.  Even when it has the exact same Lumetri FX layer on it...

[R Neil Haugen]

If you take the clips to 100% in program monitor, and do playback watching if you see any flickering there, can you see it? As normally at 100% I can catch the flicker bits here & there that are more noticeable noise/artifacts on export.

And as noted, if I do small amounts of various tools to get to the same point, just less in each tool, I can often avoid the artifacts.

Neil

[francis-crossman]

I have seen something like this before and it turned out to be a GPU error.  Try switching to software rendering (File>Project Settings>General>Renderer - set it to software).  I would also recommend resetting the preferences which can easily be done by holding the Alt/Option key while launching the application.

[chrisn88675818]

Hey Francis, Im running into the same problem, only my shadows appear to have blue in em. I tried to switch to software only but then I lose all the color grading and my clips look almost flat. Anyway I could bypass the changes I see in the sequence after switching to software only?

chris

[R Neil Haugen]

Chrisn,

Changing the Project settings option from Mercury Acceleration to Software Only should have no change whatever on the Lumetri panel and settings there ... it should only change how the program does the color processing, via GPU or CPU. So that in itself is puzzling.

A screengrab or two drag/dropped onto your reply could be very helpful. First, the Project settings dialog with the Mercury Acceleration option showing, and also a screengrab of the image on your screen showing the blue in the shadows.

And ... please reply ONLY by clicking the blue reply button. Clicking the grey reply icons causes this forum to "nest" the replies making it hard to see and follow the full thread.

Neil

[mardijaneb]

Was this ever resolved? I'm having the same issue. Rendering h.264 to .mp4 it's happening regardless of whether I use software only or hardware enabled, it only happens when the Lumetri LUT is applied, but I can't finish my project without it.

[R Neil Haugen]

You say when using a Lumetri LUT ... which LUT are you using? Is it one that came with Premiere, or you acquired elsewhere? What is the media involved? What are you doing to the clip within Lumetri besides the LUT?

Neil

[mardijaneb]

It occurs when I use any LUT. I am adjusting temperature, exposure, shadows and curves. However, I've realised that it only happens to the clipped blacks so have found a solution by moving the black slider so that they don't clip. It doesn't resolve the underlying issue but at least I can export this project on time.

[R Neil Haugen]

I'm a contributing author for a colorist's subscription site. A very common comment about LUTs by colorists is they are the dumbest math out there ... very usable mind you, but ... stupid. On account of the LUT having no ability to do anything but clip some low and high values in most situations.

So ... using a LUT is considered to require a method to 'trim' the outliers of the media, the blacks, whites, and saturation ... prior to the LUT in the signal processing chain. Lift any crushed blacks, lower any clipped highlights, and adjust saturation so you don't blow a channel there either.

The problem with LUTs in Lumetri is that the Basic tab processes the LUT prior to any tonal controls ... unlike say Resolve where a LUT applied to a node is processed after the control changes applied to that node. So ... when using a LUT in Lumetri, you need to be able to do some tonal work prior to the LUT after you have the LUT in place.

There are two ways of doing that ... use another instance of Lumetri or perhaps the RGB Curves effect prior to Lumetri and 'trim' the clip with that to get all pixels within needs. Or ... use the Creative tab dropdown slot to apply the LUT and do your tonal work in Basic. Which is what I most often do.

Now ... the Basic tab's blacks control is kinda odd and busted, so ... you can do a little with it, but that J-shape it can do to your pixels ain't what it should be doing. I use the Shadows control of the Basic tab mostly, and just lightly use the Blacks control to get the last few pixels in-bounds.

Still, Premiere shouldn't be doing the red-noise thing on export ... period. Please post this image and your comments over on the UserVoice system so the engineers see this directly. They do read all the posts there, I've actually talked with one of the engineers who does. And ... he wants a lot more detail in the reports than most people give him. So ... tell them what's happening there.

Neil

Neil

[G3ekbox]

Make sure your LUTs are also stored in the Media Encoder "LUTs" folder (similar to how they are stored in your Premiere Pro folder).  It seems that Media Encoder also need these LUTs to be added for it to be recognized for the exporting/rendering process.  Give it a try and let me know if it helps!  

File Path should look something like this: 

C:\Program Files\Adobe\Adobe Media Encoder 2020\Lumetri\LUTs

[R Neil Haugen]

It is NEVER suggested nor wise to put your LUTs in the Program/Package folders ... period. THAT folder tree for these apps is internally read by the item's "relative position" ... and NOT by the item's name.

So when Premiere, AfterEffects, or Mediaencoder look in the Program/Package folders for a LUT or Look, they look for "the fourth LUT/Look down (in computer alphanumeric) from the top", NOT "blue contrast upX". Each program assumes those folders are identical across all installations, and only contain those items that shipped with the application for original installation.

Please ... only ever use the appropriate locations as shown on their chart below. Sometimes, the LUTs folder here isn't created on installation, so you may need to create that folder. You will need to create the Technnical and Creative folders within the LUTs folder.

Use this structure ... and anything parked in your Technical folder here shows up in Lumetri's Basic tab, and is available for use and "seen" by MediaEncoder et al. The same for anything parked in the Creative folder ... seen in any Lumetri application across apps and for exporting.

The beauty of this is that this will work both across applications ... so Premiere, AfterEffects, MediaEncoder, and Prelude will all see the same things, and across versions. 2019 and 2020 will all see that same set of LUTs/Looks.

I have a shortcut to that LUTs folder on my desktop, so I have rapid access to adding or removing LUTs/Looks from the folders I've setup. Of course, you have to restart Premiere anytime you change either adding or removing LUTs from the computer.

Neil

[Discotechnica]

I am also experiencing the same problem.

I tried:

- adjusting bitrates from low to high (10 Mbps, 30 Mbps, 45 Mbps)

- changing from Variable to Constant Bit Rate

- software encoding

- opening the exported video in Premiere (the imported video shows the same artifact, so it's not a problem with my secondary video player)

No luck.

[R Neil Haugen]

discotechnica,

What is the media involved? Created by what?

What do the scopes show for the areas that go red after exporting? Say Waveform in YC no chroma or RGB Parade. And what are you doing to the media with which tools in Lumetri?

Neil

[Discotechnica]

Thanks for the quick response.

Media is .MP4 from a Sony a7riii with Picture Profile 9 applied in-camera ([S-Log3] gamma and the [S-Gamut3]). The LUT i'm using is allegedly built for S-Log3/S-Gamut3 (i selected those options when purchasing and they appear in the LUT filename)

Here are the scopes and settings for the sequence with the original problem:

I tried troubleshooting the source of the problem:

If I reduce the Contrast setting under Brightness & Contrast the export is fine as in the pic below. I'd rather still achieve the look of having contrast at 78, especially since it looks fine in the preview.

[R Neil Haugen]

Discotechnica,

You had left out one crucial comment ... you are applying an ancient 8-bit effect after the Lumetri effect. Ouch!

I have no idea why on earth you would use both Lumetri and then apply a Brightness & Contrast effect ... in the Effects panel, all effects have "lego blocks" after them depending on whether they are GPU-accelerated, 32-bit float math, or YUV color. NEVER use a color/tonal effect that does not have the 32-bit float lego block.

1) There are much better controls within Lumetri for controlling tonality than that ancient bit of code in the B&C effect.
2) You already are using one color correction effect, the newer, vastly improved code effect.
3) B&C is only an 8-bit effect, meaning that your image is now stripped down from processing in 32bit float to 8-bit. Why, why, why?

Within Lumetri you have the Basic tab tonal controls, the rather wondrous Curves section with not only the old-style RGB curves panel but a very good group of Hue/Sat/Luma curves, and of course the Color Wheels section with the shadows, mids, and highlights luma controls therein.

All are better math, better code than the old Brightness and Contrast. Do NOT use that old 8-bit effect.

Neil

[Discotechnica]

HOT DOG THIS SOLVED IT!

I deleted "Brightness & Contrast" and adjusted curves in "Lumetri Color" to match the previous look. Result here, looks exactly like preview:

For future readers, on Windows the lego blocks beside each filter don't show a difference but there is a handy filter at the top of the effect menu!