[iphone sdk] audio queue programming problem

Question

hello everyone, this is my first post. i am new to mac/iphone programming and need some help.
i am trying to play a simple .wav file in my iphone app and can't get it to work. here is my code.
//here is the structure i use to keep track of the data
typedef struct AQPlayerState {
AudioStreamBasicDescription mDataFormat;
AudioQueueRef mQueue;
AudioQueueBufferRef mBuffers[3];
AudioFileID mAudioFile;
UInt32 bufferByteSize;
SInt64 mCurrentPacket;
UInt32 mNumPacketsToRead;
bool mIsRunning;
} AQPlayerState;
//here is the callback function
static void HandleOutputBuffer(void *aqData, AudioQueueRef inAQ, AudioQueueBufferRef inBuffer)
//typecast the AQPlayerState struct
AQPlayerState *pAqData = (AQPlayerState *)aqData;
//if it's already done playing, return
if(pAqData->mIsRunning == true)
return;
//set up the read data
UInt32 numBytesReadFromFile;
UInt32 numPackets = pAqData->mNumPacketsToRead;
//read in from the audio file
OSStatus status1 = AudioFileReadPackets(pAqData->mAudioFile, false, &numBytesReadFromFile, NULL, pAqData->mCurrentPacket, &numPackets, inBuffer->mAudioData);
//set the number of packets in the buffer
inBuffer->mAudioDataByteSize = numBytesReadFromFile;
//increment the packet index
pAqData->mCurrentPacket += numPackets;
//enqueue the data
OSStatus status2 = AudioQueueEnqueueBuffer(inAQ, inBuffer, 0, NULL);
//stop the playback if needed
if(numPackets == 0)
AudioQueueStop(inAQ, false);
pAqData->mIsRunning = false;
//here is where i create the audio queue and buffers
//open the audio file
NSString *nspath1 = [[NSBundle mainBundle] pathForResource:@"song" ofType:@"wav"];
CFStringRef path1 = CFStringCreateWithCString(NULL, [nspath1 UTF8String], kCFStringEncodingUTF8);
CFURLRef url1 = CFURLCreateWithFileSystemPath(NULL, path1, kCFURLPOSIXPathStyle, NULL);
//open the file and get the data format
OSStatus status1 = AudioFileOpenURL(url1, fsRdPerm, 0, &aqData.mAudioFile);
UInt32 dataFormatSize = sizeof(aqData.mDataFormat);
AudioFileGetProperty(aqData.mAudioFile, kAudioFilePropertyDataFormat, &dataFormatSize, &aqData.mDataFormat);
//create the output queue
OSStatus status2 = AudioQueueNewOutput(&aqData.mDataFormat, HandleOutputBuffer, &aqData, CFRunLoopGetCurrent(), kCFRunLoopCommonModes, 0, &aqData.mQueue);
//get the max packet size
UInt32 maxPacketSize;
UInt32 propertySize = sizeof (maxPacketSize);
AudioFileGetProperty(aqData.mAudioFile, kAudioFilePropertyPacketSizeUpperBound, &propertySize, &maxPacketSize);
//set the buffer size and how many packets to read each time
aqData.bufferByteSize = 44100 * 4;
aqData.mNumPacketsToRead = aqData.bufferByteSize / maxPacketSize;
//set the current packet to be read, create the buffers and prime them
aqData.mCurrentPacket = 0;
for(int i = 0; i < 3; i++)
OSStatus status3 = AudioQueueAllocateBuffer(aqData.mQueue, aqData.bufferByteSize, &aqData.mBuffers);
HandleOutputBuffer(&aqData, aqData.mQueue, aqData.mBuffers);
//set the gain and start playback
AudioQueueSetParameter(aqData.mQueue, kAudioQueueParam_Volume, 1.0);
AudioQueueStart(aqData.mQueue, NULL);
//here is the code right below of where i create the queue and buffers
NSString *nspath = [[NSBundle mainBundle] pathForResource:@"white" ofType:@"png"];
CFStringRef path = CFStringCreateWithCString(NULL, [nspath UTF8String], kCFStringEncodingUTF8);
CFURLRef url = CFURLCreateWithFileSystemPath(NULL, path, kCFURLPOSIXPathStyle, NULL);
CGDataProviderRef provider = CGDataProviderCreateWithURL(url);
whitePNG = CGImageCreateWithPNGDataProvider(provider, NULL, true, kCGRenderingIntentDefault);
now, when it runs and, all of the audio function return a value of 0, which means successful, right? what happens is that it gets to the last line i listed (starting with whitePNG = ) and i get a BAD_ACCESS message in the debugger. that code worked just fine before i added the audio stuff, so i don't understand why it's broke now.
if i comment out the enqueue function in the callback, it will run just fine, but the return value of that is not an error, so i don't understand. i am completely new to audio programming, so i need some help. is the buffer size and packet read size wrong? i'm confused. i am trying to play a .wav file that is 16 bit, 44100 PCM.
please help, i don't see anything wrong with the code.
Message was edited by: jharkey

Answer 1

//if it's already done playing, return
if(pAqData->mIsRunning == true)
return;
this is actually
//if it's already done playing, return
if(pAqData->mIsRunning == false)
return;
i had that typed wrong in the code, but after i changed it i still get the errors.