4th Tolkien Cartoon

My brother swears that there was a 4th J.R.R.Tolkien Lord of the rings cartoon in the 70’s/80’s. He says he saw it on t.v. between Lord of the Rings (1978) and Return of the King (1980). I told him that other than those two and the Hobbit, there isn’t anything else. Does anyone know of a 4th Middle Earth cartoon movie from the 80’s or earlier? He insists that it was in rhotoscope also. Any help appreciated, thanks.