from xcode5 to xcode6-beta6, sounds are now distorted on iOS7 - core-audio

Question

I have a remoteIO application that loads and plays samples on iOS. It works fine when built with xcode5. I use iOS7 as a deployment target.
My application was originally built using the AudioUnitSampleType audio format and the kAudioFormatFlagsCanonical format flags. My sample files are 16 bits/44100Hz/Mono/Caf files.
Now I want to run it on iOS8.
Building my app with its original code on xcode6, the app runs fine on an iOS7 device but it produces no sounds on an iOS8 device.
As AudioUnitSampleType and kAudioFormatFlagsCanonical are deprecated in iOS8, I replaced them, after some researches, with float and kAudioFormatFlagIsFloat | kAudioFormatFlagIsPacked | kAudioFormatFlagIsNonInterleaved.
Now my app runs fine on iOS8 but the sounds are saturated on iOS7.
Has anyone experiences this? Any help ? Thanks, I am stuck here.
Pascal
ps : here is my sample loading method
#define AUDIO_SAMPLE_TYPE float
#define AUDIO_FORMAT_FLAGS kAudioFormatFlagIsFloat | kAudioFormatFlagIsPacked | kAudioFormatFlagIsNonInterleaved
-(void) load:(NSURL*)fileNameURL{
if (frameCount>0){
if (leftChannel!= NULL){
free (leftChannel);
leftChannel = 0;
}
if (rightChannel != NULL){
free (rightChannel);
rightChannel = 0;
}
}
soundFileURLRef=(CFURLRef)fileNameURL;
//----------------------------------------------
// 1.[OPEN AUDIO FILE] and associate it with the extended audio file object.
//----------------------------------------------
ExtAudioFileRef audioFileExtendedObject = 0;
log_if_err(ExtAudioFileOpenURL((CFURLRef)soundFileURLRef,
&audioFileExtendedObject),
#"ExtAudioFileOpenURL failed");
//----------------------------------------------
// 2.[AUDIO FILE LENGTH] Get the audio file's length in frames.
//----------------------------------------------
UInt64 totalFramesInFile = 0;
UInt32 frameLengthPropertySize = sizeof (totalFramesInFile);
log_if_err(ExtAudioFileGetProperty(audioFileExtendedObject,
kExtAudioFileProperty_FileLengthFrames,
&frameLengthPropertySize,
&totalFramesInFile),
#"ExtAudioFileGetProperty (audio file length in frames) failed");
frameCount = totalFramesInFile;
//----------------------------------------------
// 3.[AUDIO FILE FORMAT] Get the audio file's number of channels. Normally CAF.
//----------------------------------------------
AudioStreamBasicDescription fileAudioFormat = {0};
UInt32 formatPropertySize = sizeof (fileAudioFormat);
log_if_err(ExtAudioFileGetProperty(audioFileExtendedObject,
kExtAudioFileProperty_FileDataFormat,
&formatPropertySize,
&fileAudioFormat),
#"ExtAudioFileGetProperty (file audio format) failed");
//----------------------------------------------
// 4.[ALLOCATE AUDIO FILE MEMORY] Allocate memory in the soundFiles instance
// variable to hold the left channel, or mono, audio data
//----------------------------------------------
UInt32 channelCount = fileAudioFormat.mChannelsPerFrame;
// DLog(#"fileNameURL=%# | channelCount=%d",fileNameURL,(int)channelCount);
if (leftChannel != NULL){
free (leftChannel);
leftChannel = 0;
}
leftChannel =(AUDIO_UNIT_SAMPLE_TYPE *) calloc (totalFramesInFile, sizeof(AUDIO_UNIT_SAMPLE_TYPE));
AudioStreamBasicDescription importFormat = {0};
if (2==channelCount) {
isStereo = YES;
if (rightChannel != NULL){
free (rightChannel);
rightChannel = 0;
}
rightChannel = (AUDIO_UNIT_SAMPLE_TYPE *) calloc (totalFramesInFile, sizeof (AUDIO_UNIT_SAMPLE_TYPE));
importFormat = stereoStreamFormat;
} else if (1==channelCount) {
isStereo = NO;
importFormat = monoStreamFormat;
} else {
ExtAudioFileDispose (audioFileExtendedObject);
return;
}
//----------------------------------------------
// 5.[ASSIGN THE MIXER INPUT BUS STREAM DATA FORMAT TO THE AUDIO FILE]
// Assign the appropriate mixer input bus stream data format to the extended audio
// file object. This is the format used for the audio data placed into the audio
// buffer in the SoundStruct data structure, which is in turn used in the
// inputRenderCallback callback function.
//----------------------------------------------
UInt32 importFormatPropertySize = (UInt32) sizeof (importFormat);
log_if_err(ExtAudioFileSetProperty(audioFileExtendedObject,
kExtAudioFileProperty_ClientDataFormat,
importFormatPropertySize,
&importFormat),
#"ExtAudioFileSetProperty (client data format) failed");
//----------------------------------------------
// 6.[SET THE AUDIBUFFER LIST STRUCT] which has two roles:
//
// 1. It gives the ExtAudioFileRead function the configuration it
// needs to correctly provide the data to the buffer.
//
// 2. It points to the soundFiles[soundFile].leftChannel buffer, so
// that audio data obtained from disk using the ExtAudioFileRead function
// goes to that buffer
//
// Allocate memory for the buffer list struct according to the number of
// channels it represents.
//----------------------------------------------
AudioBufferList *bufferList;
bufferList = (AudioBufferList *) malloc(sizeof(AudioBufferList)+sizeof(AudioBuffer)*(channelCount-1));
if (NULL==bufferList){
NSLog(#"*** malloc failure for allocating bufferList memory");
return;
}
//----------------------------------------------
// 7.initialize the mNumberBuffers member
//----------------------------------------------
bufferList->mNumberBuffers = channelCount;
//----------------------------------------------
// 8.initialize the mBuffers member to 0
//----------------------------------------------
AudioBuffer emptyBuffer = {0};
size_t arrayIndex;
for (arrayIndex = 0; arrayIndex < channelCount; arrayIndex++) {
bufferList->mBuffers[arrayIndex] = emptyBuffer;
}
//----------------------------------------------
// 9.set up the AudioBuffer structs in the buffer list
//----------------------------------------------
bufferList->mBuffers[0].mNumberChannels = 1;
bufferList->mBuffers[0].mDataByteSize = totalFramesInFile * sizeof (AUDIO_UNIT_SAMPLE_TYPE);
bufferList->mBuffers[0].mData = leftChannel;
if (channelCount==2){
bufferList->mBuffers[1].mNumberChannels = 1;
bufferList->mBuffers[1].mDataByteSize = totalFramesInFile * sizeof (AUDIO_UNIT_SAMPLE_TYPE);
bufferList->mBuffers[1].mData = rightChannel;
}
//----------------------------------------------
// 10.Perform a synchronous, sequential read of the audio data out of the file and
// into the "soundFiles[soundFile].leftChannel" and (if stereo) ".rightChannel" members.
//----------------------------------------------
UInt32 numberOfPacketsToRead = (UInt32) totalFramesInFile;
OSStatus result = ExtAudioFileRead (audioFileExtendedObject,
&numberOfPacketsToRead,
bufferList);
free (bufferList);
if (noErr != result) {
log_if_err(result,#"ExtAudioFileRead failure");
//
// If reading from the file failed, then free the memory for the sound buffer.
//
free (leftChannel);
leftChannel = 0;
if (2==channelCount) {
free (rightChannel);
rightChannel = 0;
}
frameCount = 0;
}
//----------------------------------------------
// Dispose of the extended audio file object, which also
// closes the associated file.
//----------------------------------------------
ExtAudioFileDispose (audioFileExtendedObject);
return;
}