iPhone SDK Smaller CAF files: lower recording quality with Audio Queues?

Posted by Nick on Stack Overflow See other posts from Stack Overflow or by Nick
Published on 2009-08-24T08:32:26Z Indexed on 2010/04/06 17:33 UTC
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Filed under:

iphone

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SDK

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audio

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audio-recording

In my iPhone app I have voice recording functionality the utilizes Audio Queue voice recording functions of the SDK. I'm saving directly to CAF format and using the following settings for the AudioStreamBasicDescription reference:

audioFormat.mFormatID = kAudioFormatLinearPCM;

I can see that there are other format ids I could use like:

kAudioFormatLinearPCM kAudioFormatAppleLossless kAudioFormatAppleIMA4 kAudioFormatiLBC kAudioFormatULaw kAudioFormatALaw

My knowledge of sound formats is very limited so my question is... which of these should I use to create the lowest compressed audio recording files? Plus, are there other settings I should apply to lower the quality and filesize even further?

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