Somehow the words love fest don't cover it.

Wednesday's one-night-only concert of John Williams film music by the Philadelphia Orchestra as part of its two-week Williams celebration was bound to be good box office, with an audience exuding good will accumulated from the many popular Stephen Spielberg films that he has scored. But what unfolded at the Kimmel Center was beyond what could have been anticipated.

Planned to be two hours long, it went an for an extra half hour, with three encores led by the composer himself, who shared the conducting podium with Stéphane Denève, prompting some of the longest and loudest ovations I've heard at the Kimmel Center.

Did the Philadelphia Orchestra miss the boat by not scheduling more performances? No. More tickets would have sold. But this concert had a unique energy - the sense that this was happening only for us - that might not have erupted if part of a series.

The evening was designed to be more than just reliving your favorite musical/celluloid moments from the Indiana Jones films, not to mention Star Wars, Jaws, Dracula, and The Book Thief. Five or so video interludes had principal guest conductor Denève asking Williams the questions that a passionate and intelligent admirer would, inevitably looping around to this one: How, exactly, does he come up with his famous melodies? Now a tad frail at age 84, Williams admitted that for the first week or two of working on a film, he has no idea what he's doing. You have to love a guy like that.

Then came his Schindler's List story. At the first screening of the film with Spielberg, Williams was so moved that he had to go outside to compose himself. Then he told Spielberg that the film deserved a composer better than himself. The reply: "I know, but they're all dead."

The orchestra's performances had grandeur and buoyancy, especially under Denève. My favorite moment was principal cellist Hai-Ye Ni playing solos in music from Memoirs of a Geisha with gentle poetry in every note. As for the music itself, Williams is hard to discuss objectively because his music is so tied up with images and stories that are so much a part of the American landscape, whether it's sweaty, semi-shirtless Harrison Ford or the timelessly beautiful Kate Capshaw atop an elephant in Sri Lanka. At one point, a scene from Jaws was shown without music, and then with. As one of the few people on the planet who has never seen the film (I just never got around to it), I found the unmusical version of the scene plenty compelling, but Williams' music elegantly and efficiently focused the scene's tempo and magnified the emotional implications behind the physical action.

Film music in concert can be problematic; it's like opera without voices or scenery. Many of Wednesday's film excerpts did indeed have video images on a screen hung over the orchestra, but much music was presented on its own. There, a different kind of listening was necessary. With symphonic music, you're always aware of the starting point, the route the music is taking away from it, and how it might come full circle. With film music, it's totally linear. If you're stepping away from it to get the big picture, you're missing what it has to offer. Only once did I feel that the music didn't make its own compelling journey, and that was in an excerpt from Harry Potter and the Sorcerer's Stone.

Film music needs to utilize pre-established emotional points of reference (which is a euphemism for clichés). Big musical conclusions are obligatory for that final master shot, and there were several of those in the concert, which made the program seem a bit like a meal of desserts.

But part of the Williams brilliance is how he gives those well-used tropes his own spin, often with a rogue note, even in his marches, which seem to be projecting only the most primary emotional colors. His music is at its most adventurous - with excursions into bitonality and even microtone chords - at the beginning of a scene, and then rewards you with a tune near the end. His music is at its wittiest in the false endings.

And it's interesting to note that some of Williams' music has aged better than the images that inspired them. For example, during an extensive film montage from Close Encounters of the Third Kind, I had to wonder whether anybody has noticed how much the majestic space ship resembles a cross between the Academy of Music chandelier, the Universal Pictures logo from the 1930s, and the view from the stage of Los Angeles' Dorothy Chandler Pavilion (where the Oscars were once telecast).