I'm considering building a macOS music application in Swift. It would be primarily focused on handling MIDI data and playing audio with low latency, rather than intensive audio processing. I don't plan to support VSTs or third-party instruments, and I won't need to stretch or process audio samples in real time. Are there any major limitations or performance concerns I should expect with Swift for this kind of project?
3 Answers
If you’re choosing a language specifically to learn for maximum low-latency flexibility, C++ or Rust would give you more control over memory and scaling a large project. Swift’s reference counting can add overhead, especially in highly asynchronous or complicated code. That said, it’s not automatically a problem—if you already know Swift and design the real-time portions carefully, it should work well for this scope.
Even languages that aren’t ideal for real-time audio can work when allocations are minimized and data is handled efficiently. Keep the time-critical path simple, preallocate buffers where possible, and move non-real-time work such as UI updates, file access, and heavier processing onto other threads. MIDI processing is generally much less demanding than intensive audio DSP, so your stated requirements are well within Swift’s capabilities.
Swift should be perfectly capable for a small or medium-sized application like this. It’s compiled and doesn’t use a tracing garbage collector, which is helpful for predictable performance. The important part is keeping the real-time audio thread free from memory allocations, locks, unnecessary reference-counting work, and other operations that can cause unpredictable delays. For MIDI-heavy software with limited audio processing, Swift and Apple’s audio frameworks should be a reasonable combination.
That makes sense. I’m already comfortable with Swift, so I’ll pay special attention to keeping the audio callback predictable and allocation-free.