title: Is it possible to load a compressed audio file directly into a buffer, without conversion?
body: <p>I am developing an iOS app that must handle several stereo audio files (ranging from a few seconds to four minutes in duration) at once, playing up to three back simultaneously, synched through a Multi-Channel-Mixer-based AUGraph. My audio files are compressed – either as MP3, AAC or CAF – but when they are loaded into buffers are converted into the 32-bit <code>AudioUnitSampleType</code> format (my code is based on Apple's <a href="http://developer.apple.com/library/ios/#samplecode/iPhoneMultichannelMixerTest/Introduction/Intro.html" rel="nofollow">iPhoneMultichannelMixerTest</a>). Needless to say, with such large buffers, app memory very quickly becomes an issue.</p>
  
  <p>Apple's documentation states that iOS devices can decode one MP3/AAC file in hardware at a time, recommending CAF (IMA4) format for other files needing decoding in software. Before I develop a system for dynamically loading audio during playback I want to know if it is possible to load the compressed files into buffers directly (thereby significantly reducing memory requirements) and having my AUGraph convert them on the fly?</p>