It's a live action film based around two kids if I remember correctly, and one of them is slapped by a teacher in the very beginning. All I can recall after that is an attractive looking Mrs. Claus type character taken hostage by a giant in a cabin in the woods. I think the children try to save her. May or may not have had musical elements. Very odd film that always stuck with me, very well could have been Scandinavian.
I found it! I was being too specific with my details when googling. It's called J'ai rencontré le Père Noël, a French movie from 1984. The dubbed American version is called either Here Comes Santa Claus or I Believe in Santa Claus. And it wasn't a giant, it was an ogre!