mpeg4ip-1.5 causes the new media-libs/libmp4v2-1.5.0.1 package to be flagged for downgrading. Since mpeg4ip-1.5.0.1 has been released, bumping its version will solve this problem and keep the two packages in sync. (mpeg4ip-1.5.0.1 appears to compile successfully using a copy of the 1.5 ebuild.)
oops, was bumped in my overlay, I just totally forgot to commit it. Sorry for the delay