fd->Audio.connect (bind (&Player::process_audio, this, weak_ptr<Piece> (piece), _1, _2));
fd->Subtitle.connect (bind (&Player::process_subtitle, this, weak_ptr<Piece> (piece), _1, _2, _3, _4));
fd->Audio.connect (bind (&Player::process_audio, this, weak_ptr<Piece> (piece), _1, _2));
fd->Subtitle.connect (bind (&Player::process_subtitle, this, weak_ptr<Piece> (piece), _1, _2, _3, _4));