Centring Moving Object

There's a manual tracker that's very easy to use and doesn't require being "exacting" so you can create a more natural "flow" in the end video:

https://youtu.be/ayfVcRMgEio

The upper left view is what it looks like as you're tracking an object. The lower left view is the end result of the keyframed track showing the reflected edges and the clip on the right is the cropped view.

The intent of this tracker is for users to take action that moves across a widescreen aspect and "restrict" it into a Vertical Video or Square Video aspect (or other crops/masks). The clip is "reflected" on all edges so there are never any "black bands" and since the finished product is usually cropped down, the reflected video is not usually seen or noticeable.

Here's another example (which I'm fairly sure NO automatic tracker can handle):

https://youtu.be/UbI4ZEEnUiI

Basically, you just keyframe the location of an OSC where you want the center of action to be (the fewer the points, the smoother the result), then turn on the stabilizer and turn off the guides. Use only about 4-10 position changes per clip so: very easy and relatively fast. You just want to keep the main point of interest in view...

Fox's plugins are always the best solution but there's a way to hack the object tracker if it there isn't too much variation in the shot. I couldn't find the tutorial I was remembering but I found this one which shows basically the same thing. https://www.youtube.com/watch?v=JstYyYT4OzM

What you appear to be describing sounds impossible.

If the subject's face is moved to the centre of the screen the sides of the picture will move in and out of the frame leaving black areas at the sides and/or top and bottom.

If we could see a clip we might be able to suggest a different way of tackling the issue.

Depending on the precise nature of the video you might be able to enlarge and reposition the head to be more central.

It is difficult (impossible for me) to visualise what you are describing.

Could you post a clip on YouTube etc. that demonstrates the problem?