Export motion tracking crop without black bars

I’m using Shotcut version 23.09.29 on Arch Linux. I’m trying to convert a 4K GoPro video from 16:9 to 9:16 (dimensions 5,312 × 2,988 → 1,680 x 2,988) while motion tracking.

  1. I have used the Motion Tracker filter to follow my object and applied the corresponding keyframes to the Crop: Rectangle filter.
  2. I manually edited the cropping window to only move around horizontally, so that the visible portion is always 1,680 x 2,988.
  3. Unfortunately this retains the original 4K resolution but just adds black bars to the left and right outside of the cropping rectangle.
  4. I looked at whether the Size, Position & Rotate filter could help with changing the resolution, but I can’t get it to work.

How can I export my video in 1,680 x 2,988 resolution based on the cropped rectangle I have? Thanks for the help.

Doesn’t zooming in (using the SP&R filter) work? That’s what I do anyway when I switch from horizontal to vertical

Aha, the SPR filter indeed works. The crucial thing I was missing was to create a new project with the desired resolution and then copy over the tracking info, because changing the resolution of an existing project isn’t straightforward. Thanks.