Tony Tye, Post-Gazette Tom Roberts, shown in his Mexican War Streets home, set the mood with the music he arranged for "The Aviator." Click photo for larger image.

On New Year's Day, Tom Roberts sat in a movie theater watching Martin Scorsese's biopic "The Aviator."

But unlike others in the theater, Roberts wasn't focused on the action unfolding on the big screen, with Leonardo DiCaprio bringing the adventures of the eccentric Howard Hughes to life. His ears were tuned, instead, to the cinema's speakers, listening for the sounds of the music he either played or arranged for the film.

The film's first splashy scene, set in a nightclub, takes place against a backdrop song called "I'll Build a Stairway," which Roberts arranged. When Hughes tries to pick up a cigarette girl, the music that sets the mood is a piano solo, played by Roberts. And it's his arrangement of "Yellow Dog Blues" that plays in the background when Hughes meets Errol Flynn.

"Every one of those scenes, I blocked out the dialogue and was saying to myself, 'What did they use? What did they use?'" said Roberts, 42, a Swisshelm Park native who graduated from Taylor Allderdice High School.

He now lives in the Mexican War Streets.

"I think it's kind of typical. One of the guys in the band, one of the trumpet players, said he went three times," Roberts said. "You get so excited hearing yourself. You become ridiculously swelled with pride. I did want to jump up and say, 'That's me, that's me.'"

After graduating from Duquesne University in 1984 with a degree in music education, Roberts began his career teaching school and working with local musicians and bands.

"I never thought I'd get out of Pittsburgh," he said.

But as a stride pianist, one trained in an art refined by the world's jazz and blues musicians of yesteryear, Roberts dreamed "number one, of going to New Orleans, and, number two, going to New York City."

In the summer of 1989, Roberts caught the attention of blues/jazz man Leon Redbone, who recruited him for a tour with his band.

Roberts' first gig with Redbone was on "The Tonight Show."

"As a result of that one moment, my life was changed forever," Roberts said. "When I got back to the hotel, I had three offers from New Orleans."

When his stint ended with Redbone, Roberts headed to the Big Easy, where he honed his skills and earned a reputation as one of the country's most skilled historic jazz pianists, one who played in the style of people like Duke Ellington and Count Basie.

By 2001, he was living in Harlem and playing with a variety of bands, including Vince Giordano and his Nighthawks Orchestra. The band performed at the Cajun in Chelsea, a favorite spot for old-time jazz enthusiasts. Giordano and company had done several films, and Scorsese, who had seen them play, wanted the group for his latest picture.

"Vince called and said, 'Come out to Brooklyn; we're going to do some music.' As a result of doing that first session and doing some of the arrangement, I was given my own session."

What he wasn't given was much time.

"It was all very frantic, the way that this whole thing is done," Roberts said. "My session, we had three weeks to get ready for it. "

But the first week, Scorsese and company weren't sure what they wanted, so Roberts had to cool his heels -- or rather his hands.

The second week was much the same.

"They told me to call back in a week," Roberts said.

Finally, just days before heading to the studio, the director's vision was communicated to Roberts.

"Martin Scorsese wanted an era," Roberts said. "He had all these different pieces; he wanted to invoke the spirit of them."

With music swirling in his head, he planted himself in front of the computer at a friend's apartment and starting working.

Roberts began listening to the recordings of songs written decades ago and transcribing them -- that is, writing down every note played by each instrument.

Then, using a computer program, he began arranging, making adjustments, fixing glitches in the music and fleshing out the songs.

"It still has the feeling Martin wanted, but it becomes your own creation," Roberts said. "Some pieces are exact copies or original recordings, and some are stylistically appropriate. I pretty much locked myself in the apartment in New York until it was time to take a shower and get on the subway to go to the studio."

Ultimately the soundtrack ended up with songs that harken back to the 1920s, '30s and '40s.

"Shake That Thing," for example is a "wild and wooly pre-Depression party kind of thing," Roberts said. By comparison, "Stardust" evokes a '40s feeling and has a different tone and different sounds from earlier songs.

Roberts said the experience gave him a new appreciation for the part musicians and music play in a film.

"When you do these things, you begin to look at a motion picture differently. You see how music sets the moods, how it's used, how they chop it up. It's not necessarily the continuity of a piece. It was interesting to hear things repeated throughout the movie," Roberts said.

"The musicians have the ability, like an actor, to take on different roles. A lot of things I've done in the past have been within the realm of the jazz world. This crosses over. This is so different. This is the biggest thing I've ever done."