Testing an idea that every unhappy family is histrionic in its own way, John Wells directs Tracy Letts’ adaptation of his own prize-studded 2007 play. Here’s what happens when a venomous, painkiller-addled matriarch (Meryl Streep) and her three willful adult daughters (Julia Roberts, Juliette Lewis, Julianne Nicholson) reluctantly reconvene in their stuffy Oklahoma homestead: The place boils over with scandalous family secrets, bellicose recriminations, and possible Oscar nominations. Owing much to the dysfunctional-family tradition of Great American dramaturgy — it seems worth noting that Letts himself has performed in Edward Albee’s boozy matrimonial melee Who’s Afraid of Virginia Woolf? on Broadway — the August: Osage County movie teeters precipitously close to a camp catastrophe, only then to disappoint by maintaining unneeded respectability. Wells’ cinematic strategy seems mostly to be a matter of preserving the source play, and Streep’s mondo performance in particular, for posterity; this tactful approach is not unprecedented (see also: 2008’s Doubt) and not without rewards, but ultimately it’s not satisfying either. (Even if a more aggressive or imaginative film-language translation might just as easily have backfired or violated the material.) Co-stars Margo Martindale, Chris Cooper, Abigail Breslin, Dermot Mulroney, and Sam Shepard acquit themselves well, while Ewan McGregor and Benedict Cumberbatch seem unfortunately more confined by their roles than flattered. They all seem happy, though, to share the unhappiness. If the movie never quite gets over having derived from the play, it does at least give the cast a safe space to do its bawling and brawling.