Is it possible to make a legally meaningful distinction between porn which is
Some people think that all pornography is, in some sense, abusive. Maybe that's even analytic, if one distinguishes "pornography" from "erotica", as many people do. For what it's worth, I doubt there's any very clean way to make that distinction (these look like what Bernard Williams called "thick" concepts, if ever there were any), so let me just talk about "sexually explicit media". I don't myself see any reason to think that sexually explicit media, as such, has to be abusive or degrading or necessarily bad in some other way, even if most sexually explicit media is in fact bad in some way, such as presenting abusive sex as unobjectionable or even normal.
That said, some people like their sex rough, at least some of the time, and some people even like to roleplay situations in which one of the partners is abusive towards the other. None of that is very surprising. Human sexuality is varied and complex, just like humans.
Rough sex, in that sense, is not abusive. It is (or at least can be) fully consensual. So it seems clear that there's a distinction between sex that is abusive and sex that is rough. But if so, then there is equally a distinction between sexually explicit media that is abusive and sexually explicit media that is rough, by which I take the questioner to mean: sexually explicit media that presents a sexual encounter that is abusive and sexually explicit media that presents a sexual encounter that is rough. Indeed, a quick Internet search led me to the Rough Sex series of videos created by Tristan Taormino that, apparently, feature interviews with performers who discuss their interest in rough sex before presenting them engaged in that sort of practice. Certainly Taormino, who is a well-known author, sex educator, and self-described feminist, would not regard these videos as abusive, and they seem to be carried by at least two online "toy stores" that were founded by women and that have very high standards for what sorts of videos they sell.
So, yes, I think it's clear that it is possible to distinguish porn that is abusive from porn that is rough. But I'm not sure what's meant by "very" rough, and I'm no lawyer, so I'll not try to answer the question whether there's a "legally meaningful" such distinction.