Kdenlive can do this alone

[maiermic]

Thank you for sharing this interesting project. I'm curious what motivated you to write this in Python, while relying on a manual step with Kdenlive. Kdenlive can do this alone with not much more effort. See these tutorials:

• center using motion tracking
• zoom

Basically, you only need to create 3 effecs on your video:

1. create a motion tracking effect, analyze to create keyframes, copy keyframes, disable effect
2. create transform, import keyframes from clipboard to center
3. create transform, create keyframes for zoom/scale values

Was this not possible back then or didn't you know?

I would find it interesting to get your app working with Python only. As far as I know, Kdenlive uses OpenCV for motion tracking. OpenCV is available as Python library. So you could do it without Kdenlive 😉

[raspi]

Kdenlive can't do this kind of cropping. I went through those same tutorials. There's no zoom involved in this project, only cropping. You can't export that cropped view window as a new video file.

Kdenlive has a nice preview so you can see if the tracking was successful. You can also change the used tracker as sometimes even the OpenCV tracker fails.

[maiermic]

You don't scale to crop (black parts outside of the video), but (actually) crop by cutting the sides, do you?