For that knotty problem of checking blanking (especially masters with letterbox) I made a little gap batch fx setup. It’s only been used on adverts but seems to work quite well. I’m sharing it here in case it’s of use to anyone.
(The 2d transform on its own could be used for masters without letterbox)
It works very nicely. I was actually looking for another solution but yours popped up first. Someone was explaining a matchbox I had not used/heard of called id_Edgy
I combined your 2D_Transform and id_Edgy so that now any bad blanking screams out at me in garish yellow
