I'm new to FFMPEG. To make it simple, I've created a program that applies a negative filter to small images in png format. For some of the images, everything is fine and the transparency is maintained... But for others, FFMPEG converted the transparency to either black or white pixels.
I'm just using the command:
ffmpeg -y -i input.png -vf negate output.png
I downloaded the latest binaries for windows from https://www.gyan.dev/ffmpeg/builds/ (2024/03/25)