PortAudio on Raspberry Pi Configuring Recording of 8KHz 8-Bit Mono Sample from USB Microphone

I think I'm configuring PortAudio on Raspberry Pi correctly to gather data from my USB Microphone and configure them for XBee wireless transmission. The problem is the following line:

inputParameters.sampleFormat = paUInt8; // paInt16; // paUInt8 SOME REASON CAUSES ALWAYS IDENTICAL BUFFERS;

I want to record in Mono at 8KHz with 8-bit samples for telephony quality, but if I set the sampleFormat of the stream to paUInt8, then I alway get identical buffers in the callback. I check this by calculating the MD5Sum of the QByteArray. If I set the format to anything other than paUInt8, then I get different buffers. I have tried various values for the 'framesPerBuffer' size in the callback as well but nothing changes the values in the buffer. This exact behavior must be achievable because I have accomplished decent sound at the desired rates/sample types with ALSA and Qt5's QAudioInput ( with the same USB Microphone ).. It just seems to be PortAudio that I cannot configure properly - What am I doing wrong? Thanks!

Here is the code:

#include "audiorecorder.h"

// Startup audio capture
AudioRecorder::AudioRecorder()
{

    // Debug
    qDebug() << "Setting up Audio Recording Now";

    // Do the Audio setup
    doSetup();

}

// Do the setup
void AudioRecorder::doSetup() {

    // Variables for configuration
    int err;
    int indevice;
    const PaDeviceInfo *info;
    PaStream *stream;

    // Set up PortAudio
    err = Pa_Initialize();
    if ( err != paNoError ) {
        handlePaError(101,err,"Error initializing PortAudio: %s\n");
    }

    // Learn about default input device and look for usb device
    int numDevices = Pa_GetDeviceCount();
    int index;
    bool foundUSB = false;
    int foundUsbIndex = -1;
    for ( index = 0; index < numDevices; index++ )
    {
        deviceInfo = Pa_GetDeviceInfo( index );
        printf( "[%d] %s #in=%d #out=%d\n",
                index, deviceInfo->name,
                deviceInfo->maxInputChannels,
                deviceInfo->maxOutputChannels );
        QString portName = QString::fromUtf8(deviceInfo->name);
        if ( portName.contains("USB") ) {
            qDebug() << "Found USB Microphone: " << portName << " At index: " << index;
            foundUsbIndex = index;
            foundUSB = true;
        }
    }

    // Did we find the USB Microphone?
    if ( !foundUSB ) {
        qDebug() << "Could not find USB Microphone... Using default device...";
        indevice = Pa_GetDefaultInputDevice();
    }
    else {
        qDebug() << "Found USB Microphone!" << foundUsbIndex << Pa_GetDefaultInputDevice();
        indevice = foundUsbIndex;
    }
    if (indevice == paNoDevice) {
        handlePaError(200,0,"No default input device\n");
    }
    info = Pa_GetDeviceInfo(indevice);
    if ( !info ) {
        handlePaError(201,0,"Can't read audio input device info\n");
    }

    qDebug() << "Selected device name: " << info->name;
    qDebug() << "Selected device input channels: " << info->maxInputChannels;
    qDebug() << "Selected device default sample rate: " << info->defaultSampleRate;

    // Setup the input params
    PaStreamParameters inputParameters;
    bzero( &inputParameters, sizeof( inputParameters ) ); //not necessary if you are filling in all the fields
    inputParameters.channelCount = 1;
    inputParameters.device = Pa_GetDefaultInputDevice();
    inputParameters.hostApiSpecificStreamInfo = NULL;
    inputParameters.sampleFormat = paUInt8; // paInt16; // paUInt8 SOME REASON CAUSES ALWAYS IDENTICAL BUFFERS;
    inputParameters.suggestedLatency = Pa_GetDeviceInfo(indevice)->defaultHighInputLatency ;
    inputParameters.hostApiSpecificStreamInfo = NULL; //See you specific host's API docs for info on using this field

    // Open Specific input
    err = Pa_OpenStream(&stream,&inputParameters,NULL,8000.0,64.0,paNoFlag,paCallback,NULL);
    if ( err != paNoError ) {
        handlePaError(102,err,"Error opening audio stream: %s\n");
    }

    // Create a XBee object
    m_RouterApi = new XBeeApi();

    // Start stream
    err = Pa_StartStream(stream);
    if (err!=paNoError) {
        handlePaError(104,err,"Error starting audio stream:  %s\n");
    }

    Pa_Sleep(10000);  // This is how long to collect data in ms

    // Stop
    err = Pa_StopStream(stream);
    if ( err != paNoError ) {
        handlePaError(104,err,"Error stopping audio stream:  %s\n");
    }

    // Close down
    err = Pa_CloseStream(stream);
    if (err!=paNoError) {
        handlePaError(105,err,"Error closing audio stream:  %s\n");
    }

    // Done with PortAudio
    err = Pa_Terminate();
    if (err!=paNoError) {
        handlePaError(103,err,"Error terminating PortAudio: %s\n");
    }

}

// Audio data comes in through this callback
int AudioRecorder::paCallback(const void *in, void *out, unsigned long framesPerBuffer,
                      const PaStreamCallbackTimeInfo *timeinfo,
                      PaStreamCallbackFlags statusFlags,
                      void *userdata)
{

    qDebug() << "********* Got this many 'frames': " << framesPerBuffer;

    const char* buffer_ptr = (const char*)in;

    //Copy data to user buffer
    QByteArray data;
    for(int i = 0; i < framesPerBuffer; ++i) {
        data.append(buffer_ptr + i);
    }

    // Always the same if the Format is PaUInt8
    qDebug() << QString(QCryptographicHash::hash(data,QCryptographicHash::Md5).toHex());

    // This is a singleton which is the current one
//    AudioRecorder *currentOne = &Singleton<AudioRecorder>::Instance();
//    currentOne->transmitData(data);

    // Done
    return 0;

}

// Data ready for XBee transport
void AudioRecorder::transmitData(QByteArray data) {

    // Start the timer on the first go-around
    if ( m_CycleCounter == 0 ) {
        m_RateTimer.start();
    }

    // Create a ByteArray
    QByteArray toSendBytes(data.data(), data.size());

    // Create packet
    QString toSend = "";

    for ( int s = 0 ; s < toSendBytes.length() ; s++ ) {

        // Create Hex String
        QString hexadecimal;
        hexadecimal.setNum((quint8)toSendBytes.at(s),16);
        QString toAppend = QString("%1").arg(hexadecimal);
        QString paddedString = QString(" %1").arg(toAppend.rightJustified(2, '0').toUpper());
        toSend.append(paddedString);

    }

    toSend = m_RouterApi->createPacket(toSend.toUpper());
    //toSend = "7E 00 11 20 00 0A 0A 0A 01 26 16 00 00 01 00 48 45 4C 4C 4F 0F"; // TEST MESSAGE
    //qDebug() << toSend;
    int amount = m_RouterApi->writeToXBee(toSend);

    m_CycleCounter++;
    m_BytesSent += amount;
    if ( m_CycleCounter % 100 == 0 ) {
        QString update = QString("Transmitting Now!\nXBee Bytes / Sec\n = %1 / %2\n = %3 B/s").arg((int)m_BytesSent).arg((int)((int)m_RateTimer.elapsed() / (int)1000.0f)).arg((int)((int)m_BytesSent/((int)m_RateTimer.elapsed() / (int)1000.0f)));
        qDebug() << "Update: " << update;
        emit updateScreen(update);
    }

    // Clear it out
    toSend = "";

}

// Generic error routine
void AudioRecorder::handlePaError(int n,int err,char *s)
{

    fprintf(stderr,s,Pa_GetErrorText(err));
    Pa_Terminate();  // already had an error so quit checking
    exit(n);

}