Crop Project

[Greg Gesch]

Hi, You could try creating a screen size comp (1080×720?), drag the master comp into it then slide it on the X so its end is flush with the screen edge – it becomes Screen #1 (better to do the math and slide it the exact number of pixels). Then duplicate that comp and slide the master comp 1080 pixels along, duplicate that comp and slide etc. etc. to create each screen. Should work in theory.

[Cagdas Kara]

Hi,
In this case, even if the composition is 1280x720px, will 11520x5400px not get the entire render while it gets the render?
Can not we cut every screen from here?

Thank you.

[David Byrne]

I may be missing something but the maths doesn’t seem to add up here –

11520 x 5400

80 screens of (I’m assuming) 1080 x 720 would not look like your graphic above.

If we split 11520 by 16 (as on your graphic) we get 720 which would mean the width of each of those screen should be 720.
If we then split 5400 by 5 (as on your graphic) we get 1080.

That would give us 80 screens but in a portrait (Vertical) screens as seen below- so before we go on, what is your graphic referring to?

I’m sure I have something mixed up but please give the dimensions of each screen (if portrait lets say 720×1080 – start with width end then height). Also what is the frame rate?

You mention 1280 x 720 but with that Master Comp resolution this would give you the following image of 63 screens, and 9 half screens:

Cheers!
David Byrne
Animo Motion Graphics
Freelancer, UK

[Cagdas Kara]

Dear David,
I apologize for the wrong information.
Composition resolution 20.480 x 3600 px. I updated the resolution of each screen to 1280×720. There are 16 screens horizontally and 5 screens vertically. 16×5 = 80 screens.
Is this information sufficient?

I would really appreciate if you can help.
Because I do not know what to do.

Thank you for your help.

[Cagdas Kara]

Dear David,
I apologize for the wrong information.
Composition resolution 20.480 x 3600 px. I updated the resolution of each screen to 1280×720. There are 16 screens horizontally and 5 screens vertically. 16×5 = 80 screens.
Frame rate: 50fps.
Is this information sufficient?

I would really appreciate if you can help.
Because I do not know what to do.

Thank you for your help.

[Cagdas Kara]

Dear Dave,
Thank you very much for your detailed comment.
I’ve done everything you say and it happened.
Thank you so much.
I share the template I prepared.

[Matthew Keane]

Dave’s pencil-and-paper method is good advice but, for lazy people like me, there are some tools that can help automate the process…

If you are going to be doing a lot of large-scale LED wall projects, there is a script on AEscripts – https://aescripts.com/stagetool/ – that is designed to help layout comps for LED pixel mapping in Resolume, but it could perhaps be useful for setting up LED wall projects generally, so might be worth a look.

Personally though, any time I see a repetitive task like slicing up a giant comp, I’d start thinking about using expressions to speed up the process…

So, first of all, a shameless plug for one of my own tools (https://matkeane.com/project/watchout-display-builder-softedge-calculator), which I use for calculating the layout of grids of displays for Dataton’s Watchout software. Usually, I use it to calculate the softedge blending area between projectors, but with the softedge set to zero, it works for non-overlapping displays like LED walls too. I built it to be able to copy-paste layouts straight into Watchout, but one of the things on my to-do list is to create a direct export to AE. For the moment though, you can quickly export a list of the screen coordinates and crop values for a 16×5 wall of 1280×720 displays, and generate a lineup grid image while you’re at it.

I then imported the lineup image into AE and created a main comp at 20480x3600px with the grid image. Then I created a 1280×720 comp, dragged in the main comp, and then added an expression to the anchor point based on the comp name (which should be in the format ‘screen whatever 01’):


// Comp numbering should begin at 01.
grid_columns = 16; // Number of columns in grid.
grid_rows = 5; // Number of rows in grid.
screen_count_total = (grid_columns * grid_rows); // Total number of screens.
screen_number = thisComp.name.substr(-2,2); // Get screen number from last two characters of Comp name.
screen_id = parseInt(screen_number) - 1; // Parse chars to Int and change to zero-index value.
screen_row_id = Math.floor(screen_id / grid_columns); // Calculate row ID.
screen_column_id = (screen_id % grid_columns); // Calculate column ID.
screen_origin_x = (screen_column_id * thisComp.width) + (thisComp.width / 2); // Get screen horizontal pixel origin.
screen_origin_y = (screen_row_id * thisComp.height) + (thisComp.height / 2); // Get screen vertical pixel origin.
[screen_origin_x, screen_origin_y]


Duplicate the comp in the Project window until you have 80 comps, and each one will display the correct section of the main comp. Drag the all to the render queue and… go find something to do while AE renders your enormous main comp 80 times!

I think it would be faster to render out the master 20480x3600px comp as an image sequence, then re-import that into AE (or use it as a comp proxy) to render each screen.

Alternatively you could render only once, but add 80 output modules with different crop settings, but I don’t know how to automate setting that up. I wouldn’t be surprised if there is already a script or plug-in out there to do that…

Matthew Keane

Freelancer based in Paris, France
– Motion Graphics, Video Editing & Effects, Watchout Programming & Live Operation.

[Cagdas Kara]

Dear Matthew,
Thank you for your time.
The watchout tool went well. It will be very useful. But how do we send the generated screens to After Effects?

I also do not understand the script you share. But it seems like it would be very easy to throw out the 80 compositions that were created. I really want to find out.
Please guide me. I need to find out.

Thank you.

[Matthew Keane]

Like I said, I developed the tool to allow me to work with Watchout, so it doesn’t create AE comps for you. I used it to export a grid lineup image to check that my expression to position the master comp in individual screens was working correctly.

I added the expression to the anchor point of the main comp inside the 1280×720 screen comp. It looks at the name of the comp and uses that to calculate the position for the main comp so that the correct part is displayed in each screen. Now, in the Project window, hit ‘duplicate’ 79 times, and you end up with 80 comps showing the correct part of the main comp.

Example project (with just the first screen comp, ready to be duplicated) here:
12569_aeledwall01.zip

But – and it’s a big ‘but’ – if you make 80 copies of your main comp, you will be basically be rendering your huge master comp 80 times, and discarding pixels outside of the smaller screen comps – not very efficient. Which is why I suggested rendering the main comp out once, to an image sequence, and using that as the source in the screen comps – it will be much, much faster.

Matthew Keane

Freelancer based in Paris, France
– Motion Graphics, Video Editing & Effects, Watchout Programming & Live Operation.

[Matthew Keane]

Forgot to say: The zip file contains an AE (CC 2017) project, which has the grid image imported. Also in the zip are an XML Display Builder project file, a CSV .txt export with all the crop values for the screen comps and a screen grab of the layout project.

Matthew Keane

Freelancer based in Paris, France
– Motion Graphics, Video Editing & Effects, Watchout Programming & Live Operation.