This is an odd request Yes, there are languages that _has support for audio read/write_ \- but the point is that those languages has that support by means of packages/libraries - that kind of functionality is never in the core language.
So, if Nim doesn't have it, I guess it's because Nim users didn't need that functionality enough! So, unless someone has that itch, and scratches it ... then Nim will never get support for video read/write.