Family dead all along, thought they were being haunted?

Alright, I’m trying to figure out what movie I am remembering. I have a feeling it was a more modern movie (meaning 2000s and later). Here’s what I remember about the movie:
It was about a family who died in a house but they didn’t know they were dead. I believe the parents did but the kids didn’t. And they couldn’t open their doors because they were locked. they couldn’t leave the house. They were trapped. And they thought there were ghosts in their house because things kept changing but turns out they were the ghosts because they were dead and someone new moved into the house.

I distinctly remember that one of the kids (2 parents and 2 kids) played an instrument of some sort because the parents would tell them to go practice quite often.

I also think that there was a messed up reason the family had died, like the father killed the whole family??? But that could be me misremembering.

I’ve done some research and it wasn’t “The Others”, “The Haunter”, or “Beetlejuice”. Soooo I’d appreciate any help I could get in identifying this movie.