I have some source images which have a black background, and I would like to convert them into WebP images that have a transparent background.
I don't understand the talk about alpha channels from their documentation, so I am unsure if this is even possible with cwebp. I tried some guesswork with the arguments, but none worked.
The command I use for direct conversion from JPG to WebP is:
cwebp ./input.jpg -o ./output.webp
What would I need to add to this in order to get the black background from the input JPG to be transparent in the output WebP?
I think cwebp's options are mostly focused on compression with some limited other options for manipulating the image like cropping and sharpness.
To accomplish this task I would recommend image magick which is a general purpose image manipulation tool. that can remove the transparency, and then you can send that to cwebp.
imagick convert image.jpg -fuzz 2% -transparent black image.png
cwebp image.png -o image.webp