Power Window Curves Serious Aliasing- 18.01

I realize the Resolve has had an aliasing problem in the past using power window curves, but in version 16-17 I don't recall it being nearly as much of an issue as it is in 18.01. I've started working on a large project using 18.01 which has required a lot of curves masking and the aliasing- jaggy edges- are TERRIBLE! Is it just my imagination, or has the problem gotten worse/ come back, in this edition?

[Peter Chamberlain]

You might need to post details as no one else is reporting this

The Curve Window provides two methods of edge smoothing. Are you keeping both methods at zero?

The Curve Window provides two methods of edge smoothing. Are you keeping both methods at zero?

Initially at 0, but I adjust them to hopefully achieve a satisfactory result. Sometimes that is problematic.

Have the same issue. Version is 18.6.6.

Same problem in v18.6

Windows 10
GeForce RTX 3090
i7-11700k
64gb

[Peter Chamberlain]

Have the same issue. Version is 18.6.6.

I’m afraid that’s not helping me.

Post a one clip dra with a power window showing the issue u see.

Here is an example:
In this case I used the DR generators as background but it does the same on actual footage.

Screenshot of problem

AliasingProblem_1.1.1.jpg (86.16 KiB) Viewed 685 times

still happening in 19.1.4

In my opinion, aliasing on power windows in the color page isn't usually a problem for color grading. This is because you're typically feathering the edges, not creating precise rotoscoping masks with those curves. Aliasing likely makes things faster compared to anti-aliased edges, which aren't really necessary in most cases.

If rotoscoping in the color page is needed, you'd usually use either external mattes (which are supported) or mattes with perfectly smooth edges created using the MediaOut node in Fusion. Fusion has better rotoscoping tools and is more suited for the job anyway.

I haven't examined Magic Mask 2's edge handling closely, but that seems like the only suitable rotoscoping tool within the color page. Power windows are primarily masks for color adjustments, not precise cutouts. Therefore, if aliasing gives us faster performance for something we use so often, I'd gladly accept aliased edges because anti-aliased edges aren't really useful. If there's no speed difference or any other downside, then better edges would be great. That's my perspective on this issue, which has been raised several times, including as a feature request.

As we know, on the Color page, on the "Windows" panel, there are two ways of anti-aliasing:

1. "Soft 1", "Soft 2" etc.

2. "Inside", "Outside".

"Soft" makes the edges very blurry, which is obviously intentional. A low value of 0.8 makes it very blurry already.

"Outside", however, can add useful anti-aliasing, in my opinion. An "Outside" value of 0.8 keeps the edge pretty sharp, yet eliminates the zigzag.

But ... indeed ... there's a special problem with some edges, namely with those which are in the "south" section of the polygon.

Make a PowerCurve-polygon with 4 edges. Place the edge angles so that they are not perfectly parallel to the pixel grid, so that heavy alias occurs with long zigzag intervals. Turn off the curve control lines on the Viewer. Set the Outside value to 0.8. Notice how smooth the edges become -- except for that edge in the south.

Could that problem be related to the polygon's last closing point? No. Rotate the polygon: Notice that the problem only occurs on that edge which is currently in the south section.

As we know, on the Color page, on the "Windows" panel, there are two ways of anti-aliasing:

1. "Soft 1", "Soft 2" etc.

2. "Inside", "Outside".

Yeah I'm very aware of those control. They add feathering to the edges but they don't totally get rid of the aliasing.

It is not usually a big deal as we tend to try to have power windows that blends with the rest so I usually use the soft controls on most power windows like KrunoSmithy said, but there are these very occasional times where I need one with hard edges and it always surprise me that it has that much aliasing compared to the one in the Fusion page.

I felt that it was annoying to use Fusion as it works quite differently then the rest of resolve and it was complicated to be able to see your compositing and your color grade inside of fusion, but it seems that this has been solved in v20.

If anti-aliasing has significant impact on playback, then maybe it could be an option in the User Playback Settings in performance mode. So that when the playback is paused or when those settings are disabled you see your edges with anti-aliasing, and they would come out clean in your render as well.