This is a summary. To read the whole story subscribe to BostonGlobe.com
Philippe Béziat’s “Becoming Traviata” isn’t just a documentary about the staging of Verdi’s “La traviata” at the Aix-en-Provence Festival in France in summer 2011. Like Wim Wenders’s Pina Bausch tribute, “Pina,” it’s a work of art. Stage director Jean-François Sivadier, conductor Louis Langrée, and renowned coloratura soprano Natalie Dessay — none of them identified till the closing credits — don’t explain what they’re doing, they simply do it. But because we see the opera being rehearsed from beginning to end, and because we hear the famous arias, you can follow the story even if you’re unfamiliar with the opera — though a five-minute brush-up on the plot wouldn’t hurt.