Mystery sounds

This forum may not be the best place for this post, but I don't know where else to put it? There is some very strange thumping going on at my house.

We don't think this is an animal. It happens all day and night long, for one thing, with occasional breaks for a little while, but continuous for the most part. I didn't think it was rhythmic until I tried to make a video of it, and realized it happens every 7 to 9 seconds. There's no skittering or squeaking. And it's always in the same place.

We can't tell if it's in the attic or the walls or what. It can only be heard in one room (master bedroom). In each corner of the room it sounds like it's coming from a different spot. We checked out the attic and found no movement, no signs of rodents or pests, no sounds, nothing at all. The bedroom is between the master bath and the garage, but the sounds can't be heard in either of those places.

It actually sounds like something gently hitting the wall or ceiling, but there's nothing up there to hit. It happens when there's no wind or breeze. I thought about noisy pipes, but it seems to be up high, and I don't think there's any plumbing or anything up there. And since we couldn't find or hear anything in the attic right above the room.....

We are completely mystified. Any suggestions? I spend a lot of time in this room and it's really driving me crazy!