But the movie starts with the birth of Miraz' son, and then goes to Dr. Cornelius going to wake Caspian and helping him escape.

I was really disappointed that they cut all the Caspian-bonds-with-Cornelius stuff; it's delightful, and even if it's a bit talky, I think it could have worked well on the big screen (the stargazing stuff!) Instead we got all the Pevensies in wartime stuff, which just felt off to me.