Another less selective matching for transcoding on brand

There is a neeed to match on another attribute 'compatible_brand' when the 'major_brand' (ftyp) is too selective. Now we have 'ftypNotIn='. Works for many cases but sometimes causes unneeded transcoding. For example. Selecting on ftyp=mp42 selects all compatible_brands i.e. isommp42, mp42avc1,... A new attribute 'cbrand=' would add one more level in selection/deselection.