Set scaling quality using bicubic sampling
Learn about bicubic sampling, which scales layers by using at least four times as many pixels as in traditional bilinear sampling.
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When you change the scale of a layer inside After Effects, After Effects has to calculate how that new layer will look.
And particularly when you scale up, when you increase the scale, you're adding pixels to the image.
So how does After Effects do that?
Well, for years the mathematical calculation it used was called Bilinear.
It basically looked at pixels around each one that was being changed, and used those pixels to describe the new pixels that it was creating.
But the latest version of After Effects offers you another way to scale things.
And that's called Bicubic.
And Bicubic looks at at least four times as many pixels as Bilinear, so the quality tends to be better.
It's particularly better when you're working with images and video files.
It's not necessarily better when you're working with graphics.
So, I want to demonstrate the Bicubic and Bilinear Sampling methods in this lesson.
We're going to start off by looking at this image file.
This image file started its life looking like this.
There you go.
We're looking at this woman's right eye.
Let's go back to that comp.
I've zoomed up to 400%.
The image on the left uses Bicubic Sampling and the one here on the right uses Bilinear.
If you look pretty closely, you'll see that the Bilinear one looks kind of soft here in the skin.
And look at the highlight there.
Much sharper here on the left-hand side with the Bicubic Sampling versus the one on the right which is kind of softer-looking.
So when you're working with images or video files, the Bicubic method works better.
So how do you switch between Bilinear and Bicubic?
Well, you do it down here in the comp.
It's fairly simple; right there below that little switches, that Quality and Sampling switch there, this little box here.
You click on it once, it goes to Draft.
Click on it again, it goes to Bilinear.
Clicking on it again, goes to Bicubic.
Simple as that.
Bicubic is this curved thing.
That's Draft with the dots, and the straight line like that, the diagonal solid line like that is Bilinear.
Fairly simple.
So, I'll click it again to go back to Bicubic.
There's also a keyboard shortcut to do this.
Just select the layer that you want to change, and do Alt or Option B to go to Bilinear.
So now the one on the left is Bilinear.
And you can see it got a little bit softer there.
And then Alt or Option Shift B goes to Bicubic.
But it's so easy to click down here that you might use this here.
Let's zoom in a little bit farther.
I'm going to go to 800% by turning off those eyeballs.
This is now 800% here.
And again you see that the highlights there are sharper than they are on the right.
By the way, look what happens when you go to Draft.
Now you can see that Draft really is pretty obviously different; kind of blocky looking there, kind of chunky.
Go back over to Bilinear, they're not equal, and then Bicubic.
So, Bicubic here on the left, Bilinear on the right.
And again it's pretty sharp right there, and kind of softer-looking there.
So when you're working with images and video files, you're almost always better off using the Bicubic method.
Let's take a look at some graphics.
Take a look at this little tire here.
This guy started its life like that.
That's how it looked.
Now we're zooming way in on it here in this composition.
And if you look at it here, you may not notice any difference between Bicubic and Bilinear.
I mean they look pretty much alike.
The Bilinear one looks a little softer perhaps, but not that much different, right?
Let me go up 100% here, and take a look at that.
I'm going to drag this around here.
Let's take a look here.
This one on the top is Bicubic.
And look at the edges there.
That's called ringing.
And this is what happens when you use Bicubic Sampling on a graphic.
You may not notice it always.
I'll zoom back out here.
You may not see that here.
It may not be obvious.
But it's there.
And so generally speaking: when you work with graphics, you want to use the Bilinear Sampling method.
I'll zoom in again, so you can kind of look at the before and after.
Let's go back to 100%.
And I'll drag from this one - you can see the ringing there -, down to this one, where you don't see any ringing at all.
So generally speaking: Bilinear is the best way to go.
Let's switch to one more here.
This one started out like this - boy and his dog, tight shot here, zoomed all in 100%.
This is now Bicubic.
You can tell, because of that little curve there.
And you see the kind of ringing again, right there?
Click it again to go to the Draft mode, you'll see that it's very pixelated, and stair-stepped and aliased.
But now we'll go to Bilinear, and you don't see that ringing anywhere near as pronounced there.
I'll go from Bilinear to Bicubic.
And there you see it's much more obvious there.
Alright.
So I think you can see that Bicubic is the best way to go with video and image files.
And Bilinear is the best way to go with graphics.
Honestly, one more thing where things might get confusing.
Let's switch over to this comp of this hummingbird here.
It started its life looking like this.
Go back to the comp.
I'm zoomed all the way into 100% here, but this is vector art.
This is not pixel-based.
This is an Adobe Illustrator file.
So why are we seeing these jagged edges?
Well, I'll explain that in a second, but let's just switch between the Bilinear and Bicubic.
Here we are in Bilinear, and here in Bicubic.
And boy!
The ringing is just horrible there, right?
But this whole exercise is kind of unnecessary when you work with vector art, because most times when you work with vector art, you want to continuously rasterize it as you zoom in on it, because vector art is mathematically described.
It doesn't have to be pixel-based like this.
And to do that, you click this little switch down here, below that little star there, that little wheel there.
Click in here, and that continuously rasterizes a vector art layer.
So click on that, and it's just sharp as a tack.
So you don't need to worry about, whether it's Bilinear or Bicubic.
That doesn't make any difference.
I'll switch from Bicubic here to Bilinear by clicking through Draft, and going to Bilinear.
You see that it doesn't make any difference, whether you use Bilinear or Bicubic, because we've got continuously rasterized on it here.
So when you talk about working with Bilinear or Bicubic Sampling, you're talking about working with pixel-based assets.
