Standing before the Vienna Philharmonic on a sunny Salzburg morning was Pierre Boulez. This was an 11 o’clock concert in the Great Festival Hall. In the first line of his bio, the octogenarian Mr. Boulez is called “one of the most influential musicians of the last half-century.” That is almost certainly true, for good or ill.

The composer-conductor led a program that was mainly Mozart, with a new piece thrown in — not by himself, however. This was “… miramondo multiplo …” by Olga Neuwirth, an Austrian in her late 30s. Ms. Neuwirth has long been fond of the trumpet, which she used to study, and she has included it prominently in her compositions.

The new work is pretty much a trumpet concerto, in five movements, each called “aria” of something or other (“aria of memory,” “aria of peace”). Each movement is also assigned, and identified by, a metronome marking. I’m not sure that conductors or soloists will be thrilled by such strict instructions. But perhaps they will appreciate the guidance.

“… miramondo multiplo …” is full of outbursts, and then creepy quiet, and we hear a good bit of jazz. I thought I discerned touches of Gershwin, Bernstein, even Sondheim. At one point, we hear Handel arias: “Lascio ch’io pianga,” “Rejoice greatly.” I was listening for “Let the bright seraphim,” which is for soprano and trumpet and therefore would be perfectly appropriate, but I didn’t hear it. Maybe it passed me by.

The work is interesting, and worth taking in, but I found it formless, dribbling, and ultimately bothersome. It was certainly well played by Håkan Hardenberger, the Swedish trumpeter. He is one of the very few people to make a go of it as a trumpet soloist. The Neuwirth piece is punishing, requiring a huge range, and Mr. Hardenberger met every challenge superbly. In all five “arias” — not counting Handel’s — he played with beauty and character.

Mr. Boulez had begun the concert with Mozart’s hour-long Serenade in B flat, known as the “Grand Partita.” This piece is unusual in that it is for woodwinds and brass alone — no strings allowed (for once). I myself am not sold on the performance of these Mozart serenades in concert, wonderful as they are. It seems to me they’re most appropriate for a picnic — a picnic of the highest class, to be sure, but …

The Vienna players began with a bad entrance, and their ensembleship throughout the Partita was less than perfect. But this orchestra has many great players, in particular its principal oboe, who sang on that instrument beautifully. Hasn’t he been told that the oboe should be sort of ugly? Will they kick him out of the oboists’ guild?

(Note to our oboe-playing readers: I’m just kidding — for the most part.)

Mr. Boulez conducted solidly, competently, not having a heck of a lot to do, frankly. In fact, this concert failed really to show off his skills as a conductor, and those are considerable.

The concert ended with Mozart’s Piano Concerto in G, K. 453, a piece noble, sprightly, and divine, all three. It was played by Lang Lang, the Chinese wild child — and he played it magnificently. I have long maintained that Lang Lang is best in the Classical repertoire, particularly Haydn and Mozart. This performance confirmed my view. It must be because the music constrains him. I wish he respected, say, Rachmaninoff’s Piano Concerto in D minor as much as he does K. 453.

Don’t get me wrong, Lang Lang played his Mozart freely — with little rushings and so on. And he got too cute with the slow movement (Andante). A straighter rendition would have been more effective. But, on the whole, Lang Lang was sensible, exquisite, and irresistible. Seldom do you hear such beauty of tone. And seldom do you hear playing so full of life.

When the closing Allegretto began, the man beside me literally purred with pleasure. He was right to do so. Lang Lang captured the spirit of youthful fun in Mozart, and it was almost as though he was riding a horse — enjoying every gallop and turn, willing to go wherever. Mozart, I dare say, would have grinned, leaping to his feet.

When the concerto was over, the men of the Vienna Philharmonic did not leap to their feet — but they applauded heartily. That itself said a lot.

I’d like to close, if I may, with a fashion note — three, actually. Salzburg is a very, very formal place, even at morning concerts, and Mr. Boulez came out in a blue three-piece suit. By Salzburg standards, he might as well have been wearing a bikini.

But it gets better: Olga Neuwirth, when she came out for her bows, was wearing sneakers. And Lang Lang appeared without a tie.

I thought the Festung, the Fortress, would tumble off the mountain. But it stayed put.

The festival runs until August 31 (for more information, call 011-43-662-8045-500).