If not for the success of 8 Mile, it’s questionable whether Battle for L.A. would have been green-lighted in the first place. Whereas the popular Eminem vehicle was heavy on pathos and relatively light on music, Battle, as its name implies, focuses almost exclusively on freestyle rap scraps. The footage of oral one-upsmanship is certainly entertaining, but director Darren Doane videotaped at only two clubs — hardly a comprehensive look at Los Angeles’ hip-hop underground. Between extended passages of verbal sparring, Doane interviews the usual suspects, but their comments are neither revelatory nor varied enough to merit inclusion. (Rarely has the phrase yaknowwhatI’msayin‘ received such extensive airing.) Doane rounds out the program with underwhelming footage of DJs and B-boys duking it out. DJs are inherently boring to watch, but you have to work pretty freaking hard to make B-boys look this dull. As with most documentaries about underground rap movements, Battle is a thinly disguised love letter to its featured foot soldiers — and they’re presumably the only ones who’ll sit through it twice. YaknowwhatI’msayin’?