On April 23, Erato, a sister company of Time Warner, is releasing the video of a live performance of Schubert’s “Winterreise,” which took place on Dec. 15, 2019 at Carnegie Hall. The brilliant mezzo-soprano Joyce DiDonato, accompanied by Yannick Nézet Seguin, music director of the Metropolitan Opera, drew a capacity audience which included the writer of this article. A Simple and a Complicated Affair The first performance of “Winterreise” was a very simple affair. A few of Schubert’s friends gathered, just weeks before his death, to hear him play and sing the yet unfinished cycle. “Simple,” in the sense of “unadorned,” or “sincere,” is a key element of Schubert’s works, and strikes at the heart of his genius. Two current celebrities sang and played the same notes 192 years later, but it was far from a simple affair. Of course, complications are sometimes unavoidable. For example, an English-speaking audience necessitated …