Fast colour corrector not working after April update.

[johnnyk7917700]

I tried to add color corrector to a clip and got this.

Closed and reopened, tried different clips and different formats. Very odd. I also Reset layout.

Any ideas?

/J

[Peru Bob]

Try updating or rolling back your graphics driver directly from the video card manufacturer’s site.

[R Neil Haugen]

A puzzler ... I can't repro here. Something is off but ... what?

Well .. if somehow the Motion/Position had been changed in the ECP ...

Neil

[Kevin-Monahan]

Need more info about your system and media. Cannot repro.

Kevin

[johnnyk7917700]

Strange thing i noticed now, is that is i reset the effect , the crop changes!

I have all drivers update to date and before the april update it was working. If no one can reproduce it then i'm its my system, i will try to figure it out and update here.

[johnnyk7917700]

It gets weirder check this 🙂

[Ann Bens]

Cannot reproduce your issue: try trashing preferences.

[Carlos Ziade]

What if you nest that clip and apply fast color corrector? does the same issue occur?

or if you can test and export that clip to something other than ProRes, like Quick Time GoPro Cineform,

then import that export and apply fast color corrector, what happens?

[johnnyk7917700]

Thank for the ideas,

Nesting had same issue, and exporting with effect would crop output image too.

I tried other format/files, i have mp4s.

I am left with resetting  preferences but i want to avoid that. i like my settings 🙂

All other 'obsolete' video effects work fine. 

I'll backup the preferences and then reset an see.

[johnnyk7917700]

Ok seems GPU related, when i enable software only it doesn't happen. 😞

[R Neil Haugen]

Either update the driver or roll back one.

Neil

[johnnyk7917700]

I did, didn't work. also deleted preference folder. All other effects i tried are fine.

I'm on a zbook 15u G2 with intel and amd. 4170m

The three way colour correct will also do what i need (limit output) so it's not big deal for now.

[R Neil Haugen]

"LImit output" what do you mean?

As if you're talking about needing a video limiter for broadcast QC, you shouldn't use the ancient junk. They have a pretty good video limiter now ... use that, ​please​ ... !

It's in the Effects/Color Correction list. It's been stress-tested by various colorists and checked against station QC machines, and ... it works.

Neil

[Carlos Ziade]

so you are left to work only with software only renderer, make sure to enable that in Media Encoder when exporting from there as well... I wanted to know if you export without the effect applied to quicktime, GoPro Cineform, and after importing that to the timeline apply fast color corrector with GPU acceleration enabled, what happens?

[johnnyk7917700]

It happens to all file formats, don't see why go pro would be any different, i have avchd , propre h265, mobile phone files, everything.

Anyway i will leave this issue for now,  and avoid using the fast color corrector. i only needed to set output to 16-235 for some clips can do that with other tools.

Thanks for suggestions.

[R Neil Haugen]

i only needed to set output to 16-235 for some clips can do that with other tools.

What the ... ?

Premiere works with files according to the format/codec specs, which for most are of course Rec.709, and yea, 16-235. That's what Pr works with, and what it exports for most media. EXCEPT for some of the say image sequence and 4444 options, which are by standard full-range. So export to any of those, it will be limited range.

The mythology that Pr works in full range is just that ... mythology.

Now ... the '8 bit' scale along the right side of the Lumetri scopes does look like it's full ... but that was designed years ago, for editors to look at ... and it was decided it was simpler to give them essentially a "monitor mapping" of the pixel count.

Switch the scope to say the Waveform in YC/no chroma, the scale on the right side will show the scale for the media ... which with your media will be 16-235.

And no ... setting the scopes for 8 bit, float, or HDR has absolutely nothing whatever to do with processing of file data, those only set the scales for the right-side of the scopes. Period. Lumetri is full-on 32 bit float for all processing.

Neil

[johnnyk7917700]

From my understanding some footage shoot with sony cinegammas profiles use 107% IRE and appear clipped in premiere when they are not. So setting to 16-235 bring the details back.

Are you saying that anything over (100)235 in yc/no chroma mode is clipped footage? i though 255 was clip threshold

Confused now.

[R Neil Haugen]

0-255 is generally called "full" or "data range" ... and most 8-bit video is actually in the 16-235 "limited" or "video" range. Realistically, only a few DPX and other image sequence formats and some 4444 are by standard, 0-255.

The vast majority of Rec.709 media is recorded as 16-235.

Pr confuses the heck out of people because when the scopes are set to display in 8 bit formatting for the scale on the right side of the scope, the scale shows 0-255. So ... many folks assume that means that Lumetri is "in" 8-bit mathematically and using 'full' range ... both "wrong" for proper color.

Well ... Lumetri is always and only in 32-bit float mathematically. And ... to see scales in 16-235, you can set the Waveform type to YC or YC/no chroma. Then the right-side scale shows 16 across from 0 nits, and 235 across from 235 nits, "as it should" from say a colorist's perspective.

Now ... yes, some of the cinegamma and other camera profiles using forms of Log have intentional over-brights. Which can be a problem, especially using Log-corrective LUTs, as that over-bright area is "clipped" by the LUT. Which is why one always should use the corrective LUT as the second step in the process ... you need to apply the LUT in the processing chain, but then go to tonal/chroma controls processed before the LUT ... and 'trim' the clip into the best scope and display view of it, essentially "through" the LUT.

For example, in Lumetri, that would mean applying the log-corrective LUT say in the Creative tab's LUT slot ... then using the Basic tab Whites slider to pull the over-brights down within the 0-100 nits area so the LUT doesn't simply clip them.

This is the process followed most everywhere else. I've been after the engineers about the bad placement of the tech LUT slot in the Basic tab ... it should be processed LAST in that tab. I think they're finally understanding why, so at some point that might change. But ... not yet, clearly.

Neil

[johnnyk7917700]

P.s. What you said about adding the corrective lut in Creative tabs blew my mind 🙂

It makes a HUGE difference! , infact if i add it in basic tab it clips the footage and no correction will bring it back. But in creative i can go back up and adjust to taste.

I can't believe never seen that anywhere else and in all the colour grading tutorial i have seen.

[R Neil Haugen]

I started working with SpeedGrade some years back ( ahem/cough-cough) ... and went to books (real paper!) and ebooks by Van Hurkman, Hullfish & Fowler and others. Who all went through the proper way to use normalization LUTs.

And ... then the Premiere team came out with Lumetri, which adapted some of the color science of Sg into an at first not so great UI. The adaptations of the UI and tools over time have radically improved the ability to accomplish decent color work in Lumetri.

But ... two things still drive me nuts, and every year at NAB, I visit with the engineers ... the WRONG placement of the normalization LUT slot in the Basic tab, and ... the completely broken Blacks tool in that tab.

And ... currently ... they've been more willing to look at both items. A color engineer told me that yea, that blacks tool can do a couple things no color tools should do, so ... it's definitely under review. And ... everyone is studying all the links and material I gave them on the normalization LUT issue.

So ... maybe those will get fixed.

But my total list of things that need changing is rather ... um ... long ... got a week?

Neil

[johnnyk7917700]

make sense, thanks for the info. its indeed a very confusing subject!

[R Neil Haugen]

Oh, there's so much in video post that's sooooo confusing. Sheesh ...

Neil