Online streaming service Aereo is spending a lot of energy trying to help rival service FilmOn X appeal an order banning the company from operating. Shortly before the holidays, Aereo filed a proposed friend-of-the-court brief with the D.C. Circuit Court of Appeals, arguing that companies like itself (and FilmOn X) are allowed to capture over-the-air TV shows with antennas and then stream programs to users. Aereo officially says it doesn't support either FilmOn X or the TV broadcasters that sued the company for copyright infringement, but Aereo's proposed brief sides with FilmOn X on the key contested issue. Last week, TV broadcasters asked the appellate court to turn Aereo away, arguing that the company “essentially duplicates” FilmOn X's legal papers. “Aereo itself is a defendant in copyright cases involving the same plaintiffs and issues,” the broadcasters write. “Its proposed brief is simply an effort to circumvent [FilmOn X's] page limits.” On Thursday, Aereo responded. The company says it has “a direct interest in the issues to be decided in this case,” and that its proposed brief “presented arguments and perspectives that would be helpful and relevant to the court in this appeal.” Aereo, like FilmOn X, uses thousands of tiny antennas to capture broadcast TV and stream shows to users. Both companies say that their streams are “private,” because they're made on an antenna-to-user basis. The TV broadcasters disagree and have sued both companies for copyright infringement. The broadcasters argue that the streams to users are “public” performances, which require licenses. So far, Aereo has prevailed in an appellate court in New York and a trial court in Boston. But TV broadcasters have obtained injunctions against FilmOn X in California and Washington, D.C. In the Washington case, U.S. District Court Judge Rosemary Collyer banned on FilmOn X from streaming TV shows.FilmOn X is appealing Collyer's ban to the D.C. Circuit Court of Appeals. While Collyer's ban doesn't directly affect Aereo, a ruling against FilmOn X by an appeals court would set a precedent that could later be used against Aereo. Meanwhile, Aereo and TV broadcasters have asked the Supreme Court to step in and settle the matter once and for all. The Supreme Court could decide as early as this month whether to take the case.