-ChangeSpeedCommand::ChangeSpeedCommand(CustomTrackView *view, ItemInfo info, ItemInfo speedIndependantInfo, double old_speed, double new_speed, int old_strobe, int new_strobe, const QString &clipId, QUndoCommand * parent) :
+ChangeSpeedCommand::ChangeSpeedCommand(CustomTrackView *view, const ItemInfo &info, const ItemInfo &speedIndependantInfo, double old_speed, double new_speed, int old_strobe, int new_strobe, const QString &clipId, QUndoCommand * parent) :