Open source audio frameworks for iOS
Crudebyte has released an SDK for the JACK Audio Connection Kit for iOS developers. JACK, which is already available for Linux, Unix, Windows and Mac OS X, can route audio streams between applications and different audio hardware. To do this, JACK synchronises applications that read and write audio data at certain intervals with low latency.
The SDK includes a statically linkable iOS library and a number of Xcode projects with sample applications. Developers can use JACK to add a number of audio features to their iOS applications and to connect audio and MIDI ports of several applications to each other. An example application that demonstrates this is available in Apple's App Store. The JACK Audio Connection Kit SDK is released under a modified LGPL licence that allows statically linking the included JACK libraries; it can be downloaded from the Crudebyte's web site.
Another open source audio framework for iOS developers is The Amazing Audio Engine by Audiobus creator Michael Tyson. The Amazing Audio Engine is built on Core Audio's Remote IO system to offer low latency audio connections with built-in mixing, filtering and effects. The framework supports a large number of audio formats and bitrates and also offers audio input, recording and monitoring capabilities. The Amazing Audio Engine is licensed under the zlib licence – its source code is available from GitHub and documentation can be found on the project's web site.