Hi Stampede,
I am talking about my code, not your pseudo-code. In comment#8 I pasted my code and that is from MainGUI.

void thread::run() {
while(1) {
gPlayer->nextFrame(); // This function belong to MainGUI thread
QImage img = gPlayer->displayFrame(); // This function belong to Main GUI thread
emit sDisplayOnWidget(img); // from here I am calling SLOT function which is there in again MainGUI thread
qDebug() << "Non GUI thread" << QThread::currentThread();
msleep(400);
}
}

Please let me know whether this is correct way of doing or not???

If it is correct it's not uploading frame on the Label Widget...