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I'm trying to understand number format for aepx file for After Effect CS6 and CC

Coordinates are coded in cdat hexadecimal data. Coordinates is two number. I have made a list of number with the encoded hexadecimal value to help to understand format :

-100;-100   -> <cdat bdata="bfaaaaaaaaaaaaabbfb7b425ed097b420000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"/>

100;100     -> <cdat bdata="3faaaaaaaaaaaaab3fb7b425ed097b420000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"/>

100;200     -> <cdat bdata="3faaaaaaaaaaaaab3fc7b425ed097b420000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"/>

200;100     -> <cdat bdata="3fbaaaaaaaaaaaab3fb7b425ed097b420000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"/>

200;200     -> <cdat bdata="3fbaaaaaaaaaaaab3fc7b425ed097b420000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"/>

300;300     -> <cdat bdata="3fc40000000000003fd1c71c71c71c720000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"/>

800;200     -> <cdat bdata="3fdaaaaaaaaaaaab3fc7b425ed097b420000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"/>

800;400     -> <cdat bdata="3fdaaaaaaaaaaaab3fd7b425ed097b420000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"/>

800,5;400   -> <cdat bdata="3fdaaeeeeeeeeeef3fd7b425ed097b420000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"/>

800,5;400,5 -> <cdat bdata="3fdaaeeeeeeeeeef3fd7bbbbbbbbbbbc0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"/>

0;400,5     -> <cdat bdata="00000000000000003fd7bbbbbbbbbbbc0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"/>

800,5;0     -> <cdat bdata="3fdaaeeeeeeeeeef00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"/>

400,5;800,5 -> <cdat bdata="3fcab333333333333fe7b7f0d4629b7f0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"/>

Someone has an idea of this number format ?

VanVan
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1 Answers1

5

Not sure if it's still relevant, however I figured out that it's a double representation (big endian)

-100;-100   -> -0.0520833333333333 -0.0925925925925926
100;100     ->  0.0520833333333333  0.0925925925925926
200;100     ->  0.104166666666667   0.0925925925925926
200;200     ->  0.104166666666667   0.185185185185185
800;200     ->  0.416666666666667   0.185185185185185
800;400     ->  0.416666666666667   0.37037037037037
800,5;400   ->  0.416927083333333   0.37037037037037
0;400,5     ->  0.000000000000000   0.370833333333333
400,5;800,5 ->  0.20859375          0.741203703703704

However, those values are not exact pixels, as you might expect, they represent a coefficient. Each of them should be multiplied by your composition width and height respectively.

As far as i can tell your had 1920x1080 resolution:

0.416927083333333 * 1920 = 800.4999999999993

P.S. I'm working on aepx format research, in case you would like to contribute: https://github.com/inlife/aftereffects-project-research

Inlife
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