I suppose this guide is a PNG file?
Instead of having to find and drag a temple file in your project, you could also create a black clip on top of the Timeline and apply this Filter Set:
It is set to obscure the left and right sides of the screen and leave a 608x1080 bright area in the middle. But you can of course modify these values and save it as a new Filter Set. If you never used the Filter Set feature, you can find instructions on this documentation page.
I added a Reframe video filter that you can only add to the Timeline > Output for the next version (not yet in daily builds).
Added a Reframe button in Export > Video to make it more obvious
(I also added a Resample button with a warning dialog to guard the resolution and frame rate fields that people misuse instead of Video Mode.)
Clicking Reframe adds the filter to Output or switches to it:
You can drag this rectangle control around and resize it to even dimensions only (for codec and pixel format compatibility), but you cannot push any part of the rectangle outside of the frame.
It supports keyframes and motion tracking. Here, I tracked the white horse in the first clip only and then re-centered it.
There are presets for 9:16 (defaults), 16:9, 4:3, and Square.
Export automatically converts the project to use Size, Position & Rotate to achieve the result without actually affecting your project–you can save the Reframe filter on your project and simply disable it when you want to export without it. You can have multiple Reframe filters and the first disabled one is used on export.
The black bars you see in this embedded player are not part of the video!
