Why does MAI produce MIDI?

In order to reach a high level of musical adaptivity the music needs to be composed at runtime, note by note. This is what MAI does. New music is constructed, moment by moment, at runtime from the material in the tunes given as input. You cannot record what is not yet composed. To perform this just recently composed music, MAI needs musical instruments. Since MAI is software, a MIDI interface is the natural choice. In other words, there is no time to record the music, MAI is improvising live! 

Is the music recorded in advance?

No.

What is a State Event?

A State Event changes the value of one or many State Variables in a certain duration. For example: we have two tunes, A and B, and the state is [A=1, B=0] when starting MAI. This means we will hear A from the beginning. We then trigger a State Event S1 with target values [A=0, B=1] and duration 2 seconds. What happens then is that in the next 2 seconds there is a gradual change of the State Variables of A and B towards the target values. After the 2 second duration the state will be [A=0, B=1]. If MAI is configured wisely, the music will converge to B during the execution of the event or shortly after.

If one State Event is triggered, do you have to wait for it to complete before triggering another event?

No, you can trigger any event at any time. State Events will always bring the values of their State Variables to their targets from wherever they are.