Get world space position from depth buffer (post process)

Hi, iv’e heard that it is possible to convert the depth buffer into world space values using some semi-basic math yet i can’t find exactly what i want. I’m sure Absolute World Position returns Pixel world space but i need to be able to feed in Custom Depth and i’m pretty sure AWP uses Scene Depth only?

I’d like to know how i can do this from a post process and use Custom Depth, thanks.

I have solved my issue, i used this link to help me