What is this scary movie called?

The movie involves a group of friends and they're watching a movie
that was supposedly filmed in the 70's (in the movie they're watching,
the people in the movie they're watching run out of gas and one of the
guys walks to this house to ask to use the phone or something and gets
killed. then they all end up going to the house to investigate, and
slowly die. except for one girl) And like, everyone watching the
movie suddenly ends up in the house that was in the movie they were
watching. And slowly get killed one by one. They get dragged into a
closet that was in the movie. I cant remember that many details except
that at the end they try to get out of the theater but no one on the
outside can see or hear them banging on the front entrance of the
theater or hear them screaming. Like it's a glass door, but the only
thing people see on the outside is the inside of the movie theater.
But the people on the inside can see everything outside. I really want
to know. It's been really driving me crazy. LOL. But do you know what
its called?