connect(signal.get(), SIGNAL(decoder_stacked(void*)),
this, SLOT(on_decoder_stacked(void*)));
connect(signal.get(), SIGNAL(decoder_removed(void*)),
this, SLOT(on_decoder_removed(void*)));
connect(signal.get(), SIGNAL(decoder_stacked(void*)),
this, SLOT(on_decoder_stacked(void*)));
connect(signal.get(), SIGNAL(decoder_removed(void*)),
this, SLOT(on_decoder_removed(void*)));