How to set input for QMediaPlayer?

Question

Qt

In general, there is a player, and there is a combobox with available devices. And it is necessary that when choosing a device, the player sounds in a different output, try this:

QMediaService *svc = player->service(); 
if (svc != nullptr) 
{ 
    QAudioOutputSelectorControl *out = qobject_cast<QAudioOutputSelectorControl *> 
             (svc->requestControl(QAudioOutputSelectorControl_iid)); 
    if (out != nullptr) 
    { 
     out->setActiveOutput(this->ui->comboBox->currentText()); 
     svc->releaseControl(out); 
    } 
}

But it doesn't work: there are no errors, but it just doesn't want to get out. How to fix?