A poster in the comments section of my review of the 17-minute preview of "Sweeney Todd" (click here) quarrels with the claim that director Tim Burton has cut out an hour of the original Broadway musical while adapting it to screen. Admittedly, I haven't timed the stage version, but Burton is quite specific about minutes in our chat backstage (click here and listen to the full podcast) when describing his adaptation process.
That process, by the way, included the involvement of composer Stephen Sondheim. As Burton notes, they pored over the original show together as Sondheim said, "This can go, sure, but that should stay in. You can trim this song a bit." Burton keeps 26 songs in the film, but many of them are performed only in part. Even though he trimmed the role of Mrs. Lovett (Helena Bonham Carter) significantly to make the movie more Sweeney-centric, he kept her great songs like "Nothing's Going to Harm You" and "The Worst Pies in London." In the end, Burton says, he was thus able to chop the 2-hour, 45-minute musical to a 1-hour, 45 minute film. I'm sure he means those numbers as ballpark.