If a strip mask was used several times in the same frame, and it needed
to do byte->float conversion (e.g. mask is produced by a byte-color
strip, but then used in both a byte-color strip, and later on in a
float-color strip), then that byte->float mask image conversion was
introducing two inconsistencies:
- It was making mask alpha channel affect the result, which was not
happening with regular byte mask images, and
- It was converting float mask to scene linear space, which was
resulting in different image than with a byte mask.
Fix those issues by ensuring that all VSE modifiers can take either
byte or float mask as-is, without extra conversions. Previously, some
of the modifiers were done in a way where they only handled "(byte
image + byte mask) or (float image + float mask)" cases.
Pull Request: https://projects.blender.org/blender/blender/pulls/131355
dc063d8a80