A Masterwork, Reworked : Commentary: The brio that Glass and his troupe bring to the classic French film obviates most objections.

In 1924, Buster Keaton delighted movie audiences watching “Sherlock, Jr.” by playing a projectionist who walks down the aisle of a theater and climbs right into the movie he is showing. Friday night at Veterans Wadsworth Theater, Phillip Glass helped movies return the favor.

Glass calls his “La Belle et La Be^te” an opera for ensemble and film, but for lovers of the rhapsodic Jean Cocteau movie, a masterwork of French cinema, one of the effects this intriguing collaboration has is to make it seem as if the movie’s characters have walked off the screen and into our space.

It’s not like “La Belle” has actually come to life, half-life is more like it. Henri Alekan’s gorgeous images are still visible on a screen in back of the stage, but the original soundtrack is completely gone, replaced by a Glass score that employs four live singers whose vocal lines are synced to within seconds of the original actor’s voices.

In theory, all this might prove a problem for movie types. The singers and the musicians partially block the screen, and the light they need softens and blurs the image. But the brio Glass and his troupe have brought to the project obviates most objections. The result is not, as Glass said the Cocteau estate originally feared, “like painting a mustache on the ‘Mona Lisa.’ ” Rather it’s an intriguing and provocative collaboration, like having a favorite culinary treat prepared a boldly different way.

“La Belle et La Be^te” was in many ways a good choice for this experiment. For one thing, its vivid images, including some of the most magical sequences ever filmed, are strong enough to hold their own in any environment. And Cocteau, who believed that “mystery exists only in precise things,” wrote the kind of spare, poetic dialogue that translates smoothly into a sung libretto.

It is in the physical relationship between the singers on stage and the actors on film that “La Belle” is most fascinating, the place where the synthesis Glass hoped for successfully occurs. There is an unexpected and lovely balance between the two worlds, neither side overwhelming the other, as the alive but smaller singers manage to hold their own against the much larger but one-dimensional actors, and vice versa.

Best of all are the moments when the onstage performers, in situations where there is nothing for them to sing, turn their backs to the audience and face their counterparts on the screen. Like E.T. watching the skies, they seem to be longing to return to their real homes in the film, and the effect is almost inexpressibly moving.

What Glass’ transformations do as much as create a new medium, however, is bring up thoughts about the old one. Seeing “La Belle” this way underlines things about the film’s various components that might not come to mind after an ordinary viewing.

In the most obvious way, the absence of a soundtrack emphasizes even more than usual the original’s superb pictorial qualities, revealing how much this 1946 film has in common with the classic silent films of the mid-1920s, when a visual beauty that the cinema has rarely matched was created. In fact, experiencing Glass’ version is most similar to watching a vintage silent accompanied by one of the new and adventurous groups like the Alloy Orchestra that have recently pioneered new paths in accompaniment.

Paradoxically, Glass’ version also emphasizes how important certain minor aspects of the soundtrack are to our experience of the film. Glass seems to have realized this himself, because he has replaced several of those elements--birds twittering in the early morning, a horse whinnying, the Beast growling--in his version, and their brief presence makes us realize how much we’ve missed their absence.

For those familiar with the film, there is one further absence that, unfortunately, Glass can do nothing about. Gone completely is the somber, heartbreaking voice of the Beast, the sound, Cocteau said, of “a monster in pain,” an aspect of the original so moving that no one can have heard it without missing it here. In a more practical sense, the voice’s absence makes the theatricality in Jean Marais’ performance more obvious than it otherwise seems.

One of the more interesting questions this “La Belle” raises is how well Glass’ rhythmic, insistent music is suited to this particular film, and the answer is mixed. Not surprisingly, it gives the movie a heavier, more ominous cast, tending to work best in the more sinister moments, for instance when Belle’s father is lost in the woods or when the Beast’s hands smolder after a kill. Though the technical challenges might be daunting, it would theoretically be interesting to see what Glass could have done with a brooding silent film like “The Wind,” starring Lillian Gish.

And while the music and singing heighten the film’s emotions at times, they also add distance. Overall, not unexpectedly, the attractions of Glass’ version are more cerebral than Cocteau’s intensely emotional original. One makes you think, the other makes you feel, and having them both to contemplate is a remarkable experience.