How to resemple pcm data in iOS

I want to use AudioConverterFillComplexBuffer to convert sample rate for a pcm buffer(32k to 44.1k). But i didn't know why the voice seems changed(too many noise). Here is the main code:

struct AudioFrame {
 
    int samples;  //number of samples in this frame.  e.g. 320
 
    int bytesPerSample;  //number of bytes per sample: 2 for PCM16.
 
    int channels;  //number of channels (data are interleaved if stereo)
 
    int samplesPerSec;  //sampling rate
 
    void* buffer;  //data buffer
 
};
 
 
 
 
-(void)convertAudioFrame:(AudioFrame *)buffer outPutData:(unsigned char **)outPutData outPutDataSize:(UInt32 *)outPutDataSize{
 
 
if (buffer->bytesPerSample != self.unitDescription.mBitsPerChannel ||
 
    buffer->channels != self.unitDescription.mChannelsPerFrame ||
 
    buffer->samplesPerSec != self.unitDescription.mSampleRate){
 
 
    // describe the input format's description
 
    AudioStreamBasicDescription inputDescription = {0};
 
    inputDescription.mFormatID = kAudioFormatLinearPCM;
 
    inputDescription.mFormatFlags = kLinearPCMFormatFlagIsPacked | kLinearPCMFormatFlagIsSignedInteger;
 
    inputDescription.mChannelsPerFrame = buffer->channels;
 
    inputDescription.mSampleRate = buffer->samplesPerSec;
 
    inputDescription.mBitsPerChannel = 16;
 
    inputDescription.mBytesPerFrame = (inputDescription.mBitsPerChannel/8) * inputDescription.mChannelsPerFrame;
 
    inputDescription.mFramesPerPacket = 1;
 
    inputDescription.mBytesPerPacket = inputDescription.mBytesPerFrame;
 
 
    AudioStreamBasicDescription outputDescription = {0};
 
    outputDescription.mSampleRate = 44100;
 
    outputDescription.mFormatID = kAudioFormatLinearPCM;
 
    outputDescription.mFormatFlags = kLinearPCMFormatFlagIsSignedInteger | kAudioFormatFlagIsPacked;
 
    outputDescription.mChannelsPerFrame = 1;
 
    outputDescription.mFramesPerPacket = 1;
 
    outputDescription.mBitsPerChannel = 16;
 
    outputDescription.mBytesPerFrame = (outputDescription.mBitsPerChannel/8) * outputDescription.mChannelsPerFrame;
 
    outputDescription.mBytesPerPacket = outputDescription.mBytesPerFrame;
 
 
    // create an audio converter
 
    AudioConverterRef audioConverter;
 
    OSStatus status = AudioConverterNew(&inputDescription, &outputDescription, &audioConverter);
 
    [self checkError:status errorMsg:@"AudioConverterNew error"];
 
 
    if(!audioConverter)
 
    {
 
        *outPutDataSize = 0;
 
        return;
 
    }
 
 
    UInt32 outputBytes = outputDescription.mBytesPerPacket * (buffer->samples*buffer->bytesPerSample / inputDescription.mBytesPerPacket);
 
    unsigned char *outputBuffer = (unsigned char*)malloc(outputBytes);
 
    memset(outputBuffer, 0, outputBytes);
 
 
    AudioBuffer inputBuffer;
 
    inputBuffer.mNumberChannels = inputDescription.mChannelsPerFrame;
 
    inputBuffer.mDataByteSize = buffer->samples*buffer->bytesPerSample;
 
    inputBuffer.mData = buffer->buffer;
 
 
    AudioBufferList outputBufferList;
 
    outputBufferList.mNumberBuffers = 1;
 
    outputBufferList.mBuffers[0].mNumberChannels = outputDescription.mChannelsPerFrame;
 
    outputBufferList.mBuffers[0].mDataByteSize = outputBytes;
 
    outputBufferList.mBuffers[0].mData = outputBuffer;
 
 
    UInt32 outputDataPacketSize = outputBytes / outputDescription.mBytesPerPacket;
 
 
    self.currentBuffer = &inputBuffer;
 
    self.currentInputDescription = inputDescription;
 
 
    // convert
 
    OSStatus result = AudioConverterFillComplexBuffer(audioConverter,
 
        converterComplexInputDataProc,
 
        (__bridge void*)self,
 
        &outputDataPacketSize,
 
        &outputBufferList,
 
        NULL);
 
    [self checkError:result errorMsg:@"AudioConverterFillComplexBuffer error"];
 
 
    *outPutData = outputBuffer;
 
    *outPutDataSize = outputBytes;
 
 
    AudioConverterDispose(audioConverter);
 
    }
 
}
 
 
 
OSStatus converterComplexInputDataProc(AudioConverterRef inAudioConverter,
 
                                                                UInt32* ioNumberDataPackets,
 
                                                                AudioBufferList* ioData,
 
                                                                AudioStreamPacketDescription** ioDataPacketDescription,
 
                                                                void* inUserData)
 
{
 
 
    XMMicAudioManager *self = (XMMicAudioManager *)inUserData;
 
    ioData->mNumberBuffers = 1;
 
    ioData->mBuffers[0] = *(self.currentBuffer);
 
    *ioNumberDataPackets = ioData->mBuffers[0].mDataByteSize / self.currentInputDescription.mBytesPerPacket;
 
    return 0;
 
}