Sampling from films can be problematic as there will be so many rights holders involved. I am not aware of a Film Company Samples clearing house, although one of the specialists in this field may know who to turn to.If you got it from a soundtrack I would initially approach the label it was released on, and it you took it from a video or the telly I would approach the film company direct. They probably won't want to deal with you and will charge you far too much money. You may have to get permission from the actors involved too. If you use it without permission and they find out they will kill you. Maybe you can try the MCPS? They can offer advice.