Audiobus: Use your music apps together.
What is Audiobus? — Audiobus is an award-winning music app for iPhone and iPad which lets you use your other music apps together. Chain effects on your favourite synth, run the output of apps or Audio Units into an app like GarageBand or Loopy, or select a different audio interface output for each app. Route MIDI between apps — drive a synth from a MIDI sequencer, or add an arpeggiator to your MIDI keyboard — or sync with your external MIDI gear. And control your entire setup from a MIDI controller.Download on the App Store
Audiobus is the app that makes the rest of your setup better.
Visual Synth public beta
New app dropping shortly -- in open beta right now. Give it a spin, if you want to tweak video using a MIDI controller (you want to do that, right?).
I've got to beef up the documentation, do some demo videos, and stuff like that, but the app is pretty much done (I hope), and should be available for real shortly. Here's a link to the TestFlight if you want to check it out: https://testflight.apple.com/join/fRV1JcqM
And also, a little video capture -- I used an old Popeye cartoon (now in pubic domain) to show what you can do. The app plays nice in split-screen on an iPad, so you can tweak the video using things like Sidecar or Infinite Looper. You can drive the app using a conventional MIDI controller too.