Part of "improve filtering situation" (#116980), now strip scaling filter defaults to "Auto" which has logic like:
- No scale, no rotation, integer positions: Nearest (fastest)
- Scaling up by more than 2x: Cubic Mitchell, so you get nicer blending between pixels than with bilinear,
- Scaling down by more than 2x: Box, so that many pixels are averaged properly without too much aliasing,
- Otherwise: Bilinear
Existing strips that use Bilinear (which is default) get switched to Auto when loading older files.
All of this has an advantage that unless you have some special needs for your look, you can leave it at default and it will look decently good at either large up-scaling or large down-scaling, but not waste performance if you don't use any scaling at all. Previously none of the choices were good in "all cases": box (née subsampled3x3) only looks good when scaling down, cubic only looks good when scaling up, default bilinear leaves performance on the table when you don't use any scale/rotation, etc.
On something like Gold movie current edit, most of the strips effectively use Nearest now, except some that are translated into non-integer pixel positions; those stay effectively Bilinear.
Pull Request: https://projects.blender.org/blender/blender/pulls/117853
e1f8775807