Swift is great for writing iOS and Mac apps, and its creators also mean for it to be used as a systems programming language. However, certain traits about Swift make it officially off-limits for use in some audio/video-processing scenarios. What's the deal, is it not fast enough or what? We'll look at what media apps can and can't do in Swift, and what you're supposed to do instead. We'll also look at strategies for knowing what responsibilities to dole out to Swift and to C, and how to make those parts of your code play nicely with each other.