Charlotte Gainsbourg discusses her role in the Lars von Trier film “Melancholia,” a psychological disaster film about the end of the world. It’s set at a wedding celebration, and as the lavish ceremony threatens to come undone due to family resentments and the bride’s erratic behavior, true disaster looms above in celestial form. The planet Melancholia has suddenly appeared in the night sky, heading directly towards Earth. “Melancholia” opens November 11 at the Angelika Film Center and Lincoln Plaza Cinemas. She also discusses her recording career, and her latest album, « Stage Whisper. »