>I haven't checked, but are things like the MIDI framework still badly documented in the Swift docs?
Documentation for the entire audio stack has actually gotten quite a bit worse. Many references have been removed without new replacements being provided. In many cases, there are broken links in what little documentation remains. (For example, TN2274, which describes the USB audio stack is still around, but several of the outgoing links, for example the documentation for developing a USB audio plugin, are now broken, with the sample code deprecated and removed with no replacement.) New frameworks like AVAudioEngine simply don't document important limitations, particularly for OS X.
The Core Audio mailing list used to be a good place to get help and answers in cases where the documentation is weak, but traffic has withered and no from Apple seems to reply to messages any more. There has been a total of only four messages on the mailing list this month.
It's really a shame, because the audio stack is well-designed, but the documentation is so poor except for the basics that newcomers would have difficulty getting anything tricky off the ground.
What makes it particularly hard is that the Core Audio folks are a C++ crowd, so they use a bunch of design patterns that don’t really make any intuitive sense if you’re familiar with the other Apple frameworks.
Audio developers starting today are fortunate though because there’s AudioKit, which is the right choice for the vast majority of apps.
AudioKit is quite good, but it's a third-party solution that covers a fairly defined problem domain.
And while the AudioKit devs are among the most experienced Core Audio developers around, even they are frustrated by the lack of documentation. See, e.g., [1], where they say:
"The most important example of this is that we don’t really understand at present how to create AUs which have polymorphic input and output busses. [snip] This is fundamentally because the Apple documentation on how this is supposed to work is essentially non-existent. I undoubtedly leverages the fact that the input and output busses are KVO compliant, but this is about as much as we know. We will have to figure it out via experimentation."
Documentation for the entire audio stack has actually gotten quite a bit worse. Many references have been removed without new replacements being provided. In many cases, there are broken links in what little documentation remains. (For example, TN2274, which describes the USB audio stack is still around, but several of the outgoing links, for example the documentation for developing a USB audio plugin, are now broken, with the sample code deprecated and removed with no replacement.) New frameworks like AVAudioEngine simply don't document important limitations, particularly for OS X.
The Core Audio mailing list used to be a good place to get help and answers in cases where the documentation is weak, but traffic has withered and no from Apple seems to reply to messages any more. There has been a total of only four messages on the mailing list this month.
It's really a shame, because the audio stack is well-designed, but the documentation is so poor except for the basics that newcomers would have difficulty getting anything tricky off the ground.