Hello,
I wrote a single piece of code that need to be run in the thread, but I have problem quit'ing the QThread itself.

Qt Code: 
  1. void MainWindow::on_tb_prev_Refresh_clicked()
  2. {
  3.     vFilePrev = new videoFilePreview();
  4.         th = new QThread();
  5.             vFilePrev->moveToThread( th );
  6.  
  7.             connect( th, SIGNAL(started()), this, SLOT(threadStarted()));
  8.             connect( th, SIGNAL(finished()), this, SLOT(threadFinished()));
  9.             connect(vFilePrev, SIGNAL(finishedJob()), this, SLOT( vidPreviewFinished()));
  10.             connect(vFilePrev, SIGNAL(finishedJob()), th, SLOT( quit()));
  11.  
  12.         th->start();
  13.  
  14.     qDebug() << "gui thread: " << this->thread();
  15. }
  16.  
  17. void MainWindow::threadStarted()
  18. {
  19.     qDebug() << "Start th";
  21.     vFilePrev->makePreview( tmp );
  22. }
  23.  
  24. void MainWindow::vidPreviewFinished()
  25. {
  26.     qDebug() << "vidPreviewFinished in thread: " << this->thread();
  27.  
  28.     disconnect(vFilePrev, SIGNAL(finishedJob()), this, SLOT( vidPreviewFinished()));
  29.     delete vFilePrev;
  30. }
  31.  
  32. void MainWindow::threadFinished()
  33. {
  34.     disconnect( th, SIGNAL(started()), this, SLOT(threadStarted()));
  35.     disconnect( th, SIGNAL(finished()), this, SLOT(threadFinished()));
  36.     disconnect( vFilePrev, SIGNAL(finishedJob()), th, SLOT( quit()));
  37.  
  38.     delete th;
  39.  
  40.     qDebug() << "delete th";
  41. }
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Qt Code: 
  1. #include <QObject>
  2. #include <QDebug>
  3. #include <QStringList>
  4.  
  5. class videoFilePreview : public QObject
  6. {
  7. Q_OBJECT
  8. public:
  9.     explicit videoFilePreview(QObject *parent = 0);
  10.     void makePreview( QStringList );
  11.  
  12. private:
  13.  
  14.  
  15. signals:
  16.     void finishedJob();
  17.  
  18. public slots:
  19.  
  20. };
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Qt Code: 
  1. videoFilePreview::videoFilePreview(QObject *parent) :
  2.     QObject(parent)
  3. {
  4. }
  5.  
  6. void videoFilePreview::makePreview( QStringList fileList )
  7. {
  8.     qDebug() << "in the thread: " << this->thread();
  9.  
  10.     emit finishedJob();
  11. }
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And the problem with this is that connect( th, SIGNAL(finished()), this, SLOT(threadFinished())); never invoke SLOT(threadFinished());

Thanks for any suggestions.
Regards