[Paulo Jan]

Wow. Thanks for all those URLs. I’ll definitely make a note of them.

Anyway, I should clarify that I wasn’t actually trying to achieve a “grainy”/filmlike look, but just adding enough noise to prevent banding, as discussed in this thread:

https://prolost.com/blog/2012/2/28/denoiser-ii.html

As they say there, “just enough noise to not be noticeable”.

[Paulo Jan]

The problem is that they are not in the same directory. Also, I might want to render them with the same effects that I’ve applied to them in the comp.

(Yes, I want to render the clips regardless of their in/out points in the comp… but preserving whatever effects they have in the comp. Confusing? 🙂 Long story).

[Paulo Jan]

Why don’t you create your captions in AE as comps, and then import them via Dynamic Link into Premiere? This way, they behave in Premiere as pieces of footage, and you can move them, trim them, etc.

[Paulo Jan]

I can confirm that’s the cause of the behaviour that you guys are seeing. Basically, if you check “scale to frame size” in Premiere, it will create a precomp in AE.

[Paulo Jan]

I thought so, but now that I see it… no, it’s at 70%. (I assume that you mean the reflection parameter in the floor material). Is that important?

[Paulo Jan]

Okay, let me explain. I’m trying to port to After Effects this Bridge script:

https://davidmilligan.github.io/BridgeRamp/

Which deflickers an image sequence. The way it works is by computing an histogram of every selected image, then comparing the brightness level of a given percentile and adjusting the images’ exposures until they all match.

For it to work, I need to access AE’s composition as a bitmap, measuring the pixel’s RGB values to construct the histogram. That can be done using Dan’s method, though it’s a bit kludgy…

…but the script also provides a preview of which parts of the image are in a given percentile. You select a value, hit “Preview” and it shows you in red the corresponding parts of the image. The way the script does it is by creating a temp JPG file, which is why I was asking about that in my previous question.

Now that you mention using one of the keyers… I’ll have to think about it. But still, it’s quite a kludge (reading the AE scripting guide, it’s obvious that it’s not designed to do stuff like this *at all*), and there’s also the matter of performance…

[Paulo Jan]

More generally speaking, I’d like to know if it’s possible to use either expressions or scripts to manipulate a layer/comp at a bitmap level. That is:

-Set given pixels to a certain color, based on their brightness level (as in the image above).

-Take a snapshot of the current comp and perform calculations on it as a bitmap, and then save it as a JPG.

Thanks in advance.

[Paulo Jan]

Thanks for your answer. Do you know if it’s even possible to, say, overlay an image over your comp using scripting? For example, add a red overlay to all the parts of the image that have a given value. For an example, see the attached image:

[Paulo Jan]

Thanks for your answers. I’m definitely planning to upgrade to 16Gb., since I need it anyway for After Effects work.

Anyway, I just did a quick test by taking some DSLR and Gopro footage and transcoding it to ProRes LT. Then I created a fast-paced sequence using that footage, added Colorista to all the clips, and…

-No skipping whatsoever. Smooooooth playback.
-CPU usage much lower, as expected (around 20%).
-Memory usage also lower.

So I hope that the last point is the key one and the bottleneck is in the memory, instead of the CPU (since the latter would involve upgrading the entire system). I’ll perform more tests after I’ve added the 16 GB. of RAM.

[Paulo Jan]

Thanks to both. This was all happening in CS6 on Windows 7, and in the end, I managed to get to a Mac with AE installed. I opened the project there… and whew, it worked. I disabled the expressions, saved again, and problem solved.

I hadn’t thought of this solution at first because, since it was a bug in AE, I assumed that it would occur in every version.