Record sound in compressed format

[Alex.be]

I would like to modify the SpeakHere to record the file in a compressed format, and Apple released a tech note recently in order to do that but I cannot get it to work despite following instructions to the letter.

Also be careful the // make sure the audio session is active before asking for properties comment means you need to move some initialization code from the recOrStop method to the initwithnibname part - i did that.

has anyone had success modifying the example to record in an
IMA/ADPCM (aka IMA4) - kAudioFormatAppleIMA4 or similar?

Technical Q&A QA1615 - "Audio Queue - Recording to a compressed audio format."

proposed change:
SpeakHere - initWithURL: in AudioRecorder.m:

- (id) initWithURL: fileURL {
    NSLog (@"initializing a recorder object.");
    self = [super init];

    if (self != nil) {

        // define the audio stream basic description for the file to record into

        // record audio at the current hardware sample rate
        // make sure the audio session is active before asking for properties
        UInt32 propertySize = sizeof(audioFormat.mSampleRate);
        AudioSessionGetProperty(kAudioSessionProperty_CurrentHardwareSampleRate,
                                &propertySize,
                                &audioFormat.mSampleRate);

        audioFormat.mFormatID           = kAudioFormatAppleIMA4; // record using IMA4 codec
        audioFormat.mChannelsPerFrame   = 1;

        AudioQueueNewInput(&audioFormat, ... );

        ...

    }

    return self;
}