This is something I want to do:
- Open a 1920x1080 60fps video in the Source tab or Timeline, set the video mode to Square 1080p 60fps, apply a Grid filter, change its parameters, and export.
- Leave the top and bottom background #000000 rectangles in tact.
But every time I do this, some strange things occupy the black background rectangles.
Similar thing happens when I open a 16:9 video file in a non-standard custom 21:9 video mode, or a 4:3 video file in a 16:9 video mode.
Tested on v21.10.31 on Windows.