Input support for macOS

[michaeltyson]

Currently, there are issues with receiving audio input on macOS, resulting in CannotDoInCurrentContext errors when rendering. I suspect this is related to sample rate, and that an AudioConverter will be required when the input unit's rate doesn't match the output unit's one. This is only a theory, though.

[32Beat]

I frequently got CannotDoInCurrentContext when the renderslice sizes don't match. i.e. if the input device has been set with a 512 frame slicebuffer, then AudioUnitRender will only do 512 frames.

[michaeltyson]

Ah, that's such a dumb error message to use for that case - so unhelpful 😅

Pretty sure the frames per slice is set correctly, though - I did a little digging and sample rate's my best guess so far

[32Beat]

Does the input module actually attach an input device to the audio unit?

[32Beat]

line 95:

#if !TARGET_OS_IPHONE
    NSAssert(!(self.outputEnabled && self.inputEnabled), @"Can only have both input and output enabled on iOS");
#endif

should probably change to something like:

#if !TARGET_OS_IPHONE
    NSAssert(!(self.outputEnabled ^ self.inputEnabled), @"Must have either output or input enabled, (but not both)");
#endif

having both input and output enabled on the desktop didn't work for me. Likely not possible as the input will be running in its own thread.

[32Beat]

https://github.com/32Beat/TAAE2/tree/MacOS_InputModule