Problem with ProRes 422 HQ codec

The camera recorded file seems quite clean to me. The Ninja file has the little gaps in the Parade and Waveform scopes which the camera footage does not. The fine horizontal dark lines running across the scopes. That typically is missing data at that 'level'.

This camera file is not really what I'd call "log".  The black point is lifted to about 20, the highlights dropped to what, 90? And the saturation is low.

So it was simple to 'normalize' For the shadow/black, I went to the Color Wheels, and pulled the Luma slider of the Shadow wheel set down until black point was around 4 or 5 on the nits scale on the left side of the scopes.

Then pulled the image up very slightly ... with the Exposure control. Didn't need much just a tiny amount, so to 0.1 on the Exposure settings. Takes the white point just above 90 on the left-side nits scale.

And I went to the Creative tab and lifted Vibrance to 39. That's it.

Neil

Here's some more images of the scopes signal. This is the Nikon recorded image, frame 1, no LUT:

Here's the Ninja recorded frame 1, again no LUT:

And here's the Nikon with the z-Log LUT:

 And the Ninja with the z-log LUT:

 Here's the Ninja, Waveform RGB, no LUT:

 And the Ninja, Waveform RGB, z-log LUT:

I've got a few comments. First, the media recorded internally is on my system higher quality than that recorded on the Ninja. Look at the smoothness of scopes on the original Nikon versus the Ninja, both without the LUT.

Next, that LUT is stressing the media to, and really, past the breaking point. First, talking about the color changes it makes. Look at the Vectorscope changes, between no LUT and LUT applied, both on the camera recorded clip and the Ninja recorded clip. That LUT is pushing some data out actually slightly past the out-of-bounds lines of the Vectorscope. This is an extreme lifting of color data.

And here's the same image, again, first frame of the Nikon camera clip, lowering of the Shadows Luma control of the Color Wheels tab to bring Black down to about 4-5 nits, and slight boost to the Exposure control of the Basic tab,  just 0.1 up. With Creative tab's Vibrance control to 39. No banding. Image goes from 4 nits to 96 nits, with good "normal" color.

From this, I've got a concern with both the Ninja recording and with that LUT. No problem with the original media.

Neil

Ok, just got them into Premiere. This is the original Nikon recorded file. And the signal trace in the scopes is not something I'm used to seeing.

That solid line at the bottom is just odd to me. I've not seen that sort of thing before. Plus there's a big divide between where most of the "upper" data would be, I'm assuming the sky, and the bright spots of the buildings on the left. The sky is pretty compressed, but the lights of the buildings are quite a ways above them.

I'll spend a bit more time with all of the clips in a while.

Neil

I got a pretty ouchie conclusion and honestly, I can't believe my eyes. I took the h.265, and encoded it to Prores HQ with shutter encoder. I then did a basic curves adjustment and saturation increase and got really bad banding in the sky. I took the Prores HQ I just transcoded and trancoded it again to h.264, copied the lumetri effect with the settings over and the sky was perfect. Semi-good news, Prores 444XQ works ok. The only conclusion I can draw is that there are many codecs that have premiere bugs. Since the banding is there before the lut, the lut would simply exacerbate the bug.

additional note: I forced Prores 444HQ back to 16-235 and got some banding back, so there may be a corralation of video levels. also h.264 which looked perfect, did have a 10% boost in gamma.

but I think there's enough here that a color engineer needs to sit down and take a look.

 That is 'banding' technically, caused by the application of the LUT.

Are you applying the LUT in the Basic tab slot of PrPro? If so, try applying it from the Creative tab slot instead, then go into the Basic tab and adjust the White and Highlight controls a titch, see if you can get rid of it.

Colorist's call LUTs the dumbest math out there. Nearly all LUTs can and will clip and cause banding and artifacts unless the user has the ability to apply some 'trim' to the exposure, contrast, and saturation before the LUT while viewing the image with the LUT.

Hence my suggestions.

Neil