Martial artists often find the film fight style to be unnatural - it goes against everything they've learnt. They have to learn to adapt the real moves they know to the reel style. Bruce Lee's movies reflected a very different style of jeet kun do to that he taught as self defence.

Judo and aikido break falls and rolls can be useful for fight scenes and stunts involving minor falls.

Stage combatants have a slight advantage over martial artists as their sword and staff techniques are much closer to film/TV fight techniques than what is taught in the dojo. Similarly, if they have done combat mime or other unarmed stage combat training, they know the type of techniques that "sell" punches and kicks in fights to an audience. To make a fight look good you have to act.  How to throw a movie punch by Manny Siverio explains the basics of fight choreography. The rest of his site is also well worth checking out.

Both martial artists and stage combatants need specialist training for other stunts: cars, high falls, fire, etc.