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IAA Details features, functions, options, and issues associated with IAA Inter-App Audio.

1. Generator apps create sounds.
2. Instrument apps can have MIDI sent to their IAA MIDI port to control them.
3. Effect apps receive an audio signal and effect it in some way.
4. MIDI Effect an effect app that can be controlled via MIDI sent to its MIDI port. An IAA app may listen for MIDI or have a virtual port even though it's only an IAA app (this can be very confusing). You may have setups where there can be duplicate MIDI messages being sent to the same IAA app which creates problems or you may need a third app to receive MIDI and send it on to the final destination.

IAA Host Sync an IAA host app must have implemented host sync and the IAA app must have host sync to sync up to the host's transport controls. This sync is sample accurate.

Audiobus 3 Supported Apps Audiobus 3 is an app that uses IAA to host apps provided the IAA app developer included Audiobus support into their app for it to run inside Audiobus (using the free Audiobus supplied SDK).

1. Audiobus State Saving means the IAA being hosted will have its settings saved when you save a preset for a setup in Audiobus 3. For example, a synth app would have the preset you were using saved when you save the setup as a preset in Audiobus.
2. Not all apps with Audiobus support have state savings.
3. Audiobus Remote is an app created by the Audiobus developers which allows you to remotely control the apps in an Audiobus setup provided the app being hosted has Audiobus Remote support.
4. Some apps can be both IAA hosts and have Audiobus support so they can be hosted inside Audiobus. Example, GarageBand can only be hosted inside Audiobus as output so you can route your audio from Audiobus into it. Others like Moebius Lab and apeMatrix can only be input sources. Some like AUM, Cubasis, Audio Evolution Mobile Studio, and modstep support input and output.

IAA Zombies is a bug that occurs when you have IAA apps hosted in an IAA app host, you close the host, and the IAA app continues to run in the background. Even when you check to see if the app is open, it may not appear. The app running in the background will continue to use resources on your iOS device and can cause your iOS music setups to crash. Bringing the IAA app to the foreground and then closing it can help to minimize IAA zombies. Opening and closing the app in the setup can resolve the issue too.