I found this article about how sound was recorded for Les Miserables, the 2012 musical starring Hugh Jackman, Anne Hathaway, and Russell Crowe (the best part of the article is the video that it features interviews with the cast discussing what the process of singing live was).
I think that it is interesting to compare a musical film like Les Miserables to Bride and Prejudice, not only to compare style and production values, but also to see how the songs were recorded and featured in the film. In Bride and Prejudice, all of the songs were pre-recorded and laid over the visual footage of the film, so the actors had to mime what they were “singing” on film while shooting. Even though that makes the sound a little more polished, the visuals can get a little funky when the lyrics don’t always sync up perfectly with the actor’s lips (it can occasionally look a little cheesy).
On the other hand, Les Miserables goes for somewhat of a more natural, Broadway-style approach by having the actor’s sing live, and while this is pretty interesting, it also sets up enormous risks and imperfections in the performances. The voices and music may not sound as impeccable as they would in a recording studio, but maybe that is what the film was going for. Either way, their decision to use live-footage of the singers was hit-or-miss with audience members, some who found it a fantastic divergence from traditional musical styles, while others found it too distracting. It is an interesting take on making a musical regardless and it would be interesting to see if more movies will take this approach in the future.