core audio - AUGraph setup on iOS -

I am preparing an article for an iOS application and appreciate the help in the following points.

If I want to play several audio files at once, do each file need an audio unit? From Core Audio Docks

Linear PCM and IMA / ADPCM (IMA 4) Audio You can run many linear PCM or IMA 4 formats in iOS without a CPU resource, with AAC, MP3 , And AAC, MP3, and App Lossless (ALAC) audio playback for app, MP3, and Apple Lawless (ALAC) use efficient hardware-based decoding on the iPhone and iPod touch. You can only play such a sound at a time.

So many AAC or MP3 files can not be played at the same time. What is the optimum LPCM format to play more than one sound once?

Does this also apply to audio-unit, because this audioquality is under document.

Is an audio unit AUGraph inactive? If an AUGraph looks like this

speaker / output & lt; Recorder unit & lt; Mixer unit & lt; Number of audio filing units

What if the recorder is not active, can it still drag, but do not have to type the buffers in the file?

No; You need to use a mixer audio unit to check it:

By reading the above document mostly, by creating a pair of utility structures by wrapping the sample code in a class, I get this simple sound engine scratched Coded with:

TTP: //nicolasmiari.com/blog/a-simple-sound-engine-for-ios-using-the-audio-unit-framework/ (In my blog Articles linked with source code). Sorry, the blog was taken to Jakeel / Github and this article was not cut.

... I was going to start a repo on Github, but it is very difficult. I am a visual man, yet too much git-phobic Okay, it was a long time ago ... now I'm using GIT from the command line: -)

You can use it as, or audio unit Extract the code related to and optimize it for your project. I believe that the Cocos Dansion 'simple audio engine' does more exactly the same thing, but has not tested the source code.

Known Issues If you have an exception break point C + + exception, when debugging, code 2 or 3 times close to AUGraphInitialize () Will be done. This is a 'non-crashing' exception, so you can click continue and the code works fine.

Uncompressed your WAV files. To convert to CAF format, use this command on the terminal:

 % afconvert -f caff -d LEI16 mysoundFile.wav mySoundFile.caf   
  Edit:  So I created a Geethb repo after all: