How to program a real-time accurate audio sequencer on the iphone?

Question

I want to program a simple audio sequencer on the iphone but I can\'t get accurate timing. The last days I tried all possible audio techniques on the iphone, starting from Audio

Answer 1

One additional thing that may improve real-time responsiveness is setting the Audio Session's kAudioSessionProperty_PreferredHardwareIOBufferDuration to a few milliseconds (such as 0.005 seconds) before making your Audio Session active. This will cause RemoteIO to request shorter callback buffers more often (on a real-time thread). Don't take any significant time in these real-time audio callbacks, or you will kill the audio thread and all audio for your app.

Just counting shorter RemoteIO callback buffers is on the order of 10X more accurate and lower latency than using an NSTimer. And counting samples within an audio callback buffer for positioning the start of your sound mix will give you sub-millisecond relative timing.