How can I prevent audio application to abort?

[davidlamhauge]

I am programming a lip-sync software for animation.
I take a .wav file, and split its 44100 samples pr.sec into 25 or 30 equally big chunks, depending on chosen frames pr. sec.
I have a QTableWidget, where I can enter characters for every frame. Every character is mapped with a picture of a mouth, and when I press SPACE I hear the audio, and see the pictures in sync with the audio. No problems

When I want to search in the audio, frame by frame, I can do it with the up/down-arrow keys. It works if I press these keys two or three times pr. sec., but if I hold one of the keys down, the application crashes. Why?
I would like to avoid hacks like sleep-functions, but what should I do?

Here is the code that plays the active frame.

mouthFrame = activeFrame;
    QFile audioFil(audioFileName);
    if (audioFil.open(QIODevice::ReadOnly)){
        int offset = dataOffset + 8 + ((activeFrame - 1) * samplesPerFrame * blockAlign);
        audioFil.seek(offset);
 
        ba = audioFil.read(i * samplesPerFrame * blockAlign );
        audioFil.close();
        QBuffer* audioBuffer = new QBuffer(&ba);
        audioBuffer->open(QIODevice::ReadOnly);
 
        output = new QAudioOutput(format,this);
        output->start(audioBuffer);
        output->setNotifyInterval(1000/fps);
 
        QEventLoop loop;
        connect(output, SIGNAL(stateChanged(QAudio::State)), &loop, SLOT(quit()));
        connect(output, SIGNAL(notify()),this, SLOT(showMouth()));
        do {
            loop.exec();
        } while(output->state() == QAudio::ActiveState);
        output->stop();
        audioBuffer->close();
        delete output;

mouthFrame = activeFrame;
    QFile audioFil(audioFileName);
    if (audioFil.open(QIODevice::ReadOnly)){
        int offset = dataOffset + 8 + ((activeFrame - 1) * samplesPerFrame * blockAlign);
        audioFil.seek(offset);

        ba = audioFil.read(i * samplesPerFrame * blockAlign );
        audioFil.close();
        QBuffer* audioBuffer = new QBuffer(&ba);
        audioBuffer->open(QIODevice::ReadOnly);

        output = new QAudioOutput(format,this);
        output->start(audioBuffer);
        output->setNotifyInterval(1000/fps);

        QEventLoop loop;
        connect(output, SIGNAL(stateChanged(QAudio::State)), &loop, SLOT(quit()));
        connect(output, SIGNAL(notify()),this, SLOT(showMouth()));
        do {
            loop.exec();
        } while(output->state() == QAudio::ActiveState);
        output->stop();
        audioBuffer->close();
        delete output;

To copy to clipboard, switch view to plain text mode 

As I said, it works if you're patient...
Could it be improved?

David