global_mixer = new Mixer(QGLFormat::toSurfaceFormat(format()), global_flags.num_cards);
global_mainwindow->mixer_created(global_mixer);
global_mixer->start();
global_mixer = new Mixer(QGLFormat::toSurfaceFormat(format()), global_flags.num_cards);
global_mainwindow->mixer_created(global_mixer);
global_mixer->start();