how to export a list of png files into a list of alpha black and white png image files

[LaoMar]

Hello to everyone.

I'm trying to rotoscope a list of 187 png pictures using the tool rotobrush because I want to convert them into a list of png black and white alpha images,like these that you can see here :

https://drive.google.com/open?id=11HHgS7U8wnC_wpZMeEIpiKF2fOOfLEi-

I would like to know how to save / export all these 187 images in black and white,alpha sequence. I have also made a post here :

https://www.reddit.com/r/AfterEffects/comments/ekl550/how_to_save_convert_a_list_of_png_files_into_a...

and the user "ikiper" told me to do this :

"File - export - media Than you should select PNG,and rgb+alpha. İt will export every frame as png image with alpha"

but I'm not able to reach the result that I want. Infact this is how should be :

https://drive.google.com/open?id=1cpbzsmdc3UCL-bLs0tlGaSZYHYpuonz9

instead,this is how it is :

https://drive.google.com/open?id=1R3K4Oyrw_6-E1IyDYArOzohkBcPq_pQ7

what's wrong ? thanks.

[Mylenium]

Why even use AME? Your workflow makes no sense at all. All that's required is to add the files to AE's native render queue and select "Alpha only" from the output settings. You might want to actualyl read the online help for the basics instead of relying on questionable YouTube tutorials or whatever...

Mylenium

[LaoMar]

Hello. thanks to your suggestion I've been able to understand how to do that,but I see that it is an annoying task,because the rotobrush tool is not precise. Isn't there an easier and automatic method to achieve the same result ?