Without making single iOS app Ableton made more than anybody else (including Apple) for popularization of iOS music making - it all started with Ableton Link - amazingly simple solution for syncronization of music apps (which is now also available for .
And today they've announced Ableton Export SDK and three iOS apps were updated with Ableton Live Session export - TriqTraq, Patterning and Blocs Wave.
Here's Ableton's intro video:
And here's description from Ableton website:
Ableton Live Set Export is a library that allows an application to write Ableton Live project files. The library handles generation of the ALS document, but also creates the project folder structure and copies any associated audio resources to the project. The library provides an Objective-C wrapper for iOS development.
The library only contains functionality for generating Ableton Live projects. It does not support reading or parsing Live Sets or other Ableton-generated files. This library also does not handle transmitting the project data from an iOS device to Live, or any other network operations. Ableton will provide separate UX guidelines to advise on how the library can best be integrated in your app.
Before Ableton officially released SDK there were several iOS apps that support export to Ableton Live session format - most notable Korg Gadget.