Learning Core Audio: A Hands-On Guide to Audio Programming for Mac and iOS

7. Audio Units: Generators, Effects, and Rendering

Chapter 1, “Overview of Core Audio,” roughly divvied up Core Audio’s frameworks into two general groupings: “engine” APIs that process streams of audio through the system, and “helper” APIs that work with audio in different ways, such as performing format conversions or doing file I/O. In Chapters 4, “Recording,” and 5, “Playback,” you worked with the Audio Queue, a higher-level audio engine API, and in Chapter 9, “Positional Sound,” you’ll look at OpenAL, which is also a high-level engine. Audio Queues and OpenAL are both implemented atop Audio Units, the code that’s arguably the heart of Core Audio. Audio Units are as close to the metal as most developers will ever need to get, and they afford ...