On the evidence of Alison Chernick’s able but unexceptional documentary, Itzhak Perlman is not only a marvelous musician but a lovely human being who has overcome enormous obstacles to build a career most other violists would envy while devoting himself to philanthropy and teaching as well as concertizing. Watching “Itzhak,” which is getting some theatrical exposure before migrating to television (it will be broadcast as part of the PBS American Masters series), one cannot but be charmed as well as amazed by Perlman’s virtuosity, energy and sheer humanity.

A major part of the film is, of course, simply biographical. We learn of his birth in Tel Aviv to parents who had emigrated from Poland to Israel and soon perceived his musical talent. His progress was hampered, however, by the fact that he’d been stricken with polio at age four and wore braces that prevented him from standing while he played. Potential teachers often perceived him more as a curiosity than a true prodigy. Still he persevered, and by his teen years was studying at Juilliard—one of his teachers there expresses her amazement at his talent, while looking back he admits that he found her open mode of instruction irritating then but uses it now with his students—and appeared on the Ed Sullivan Show, playing part of the Mendelssohn concerto.

His ascent from there to iconic status among violinists gets only cursory coverage, but much time is devoted to his marriage to the vibrant Toby, who gets fairly thorough biographical treatment as well and is shown discussing the contributions she has made—and continues to make—to his career. In many ways this is a joint biography, with Toby emerging as an equal partner (though not, of course, in the musical sense), and her outspokenness is no less engaging than his gregariousness.

Interspersed with the purely biographical material are scenes of Perlman playing in concert with Zubin Mehta, or practicing Bach sonatas with Martha Argerich and a Schubert trio with pianist Evgeny Kissin and cellist Mischa Maisky and sharing jokes with them as they later enjoy some Chinese take-out. Food is also featured in a session with guest Alan Alda. Perlman cooks for him (“garbage soup” he calls the dish), and Alda tells him about his own bout with polio as they share memories of the different treatments—most of them painful—that they endured.

Then there are sequences of Perlman as teacher, encouraging his young charges and then using the Socratic method he once found unhelpful. But these are juxtaposed with plenty of glimpses into Perlman’s life—waiting for a sleeping homeless man to be escorted from a recording studio restroom so he can use it; navigating his electric cart through a snow-covered New York sidewalk; playing the national anthem at a Mets game, or what he says is the most requested item in his repertoire, John Williams’ theme from “Schindler’s List”; visiting a violin store, where the owner shows him an instrument with a swastika and the year “1936” written inside the case, and a repairman who looks over his own beloved Stradivarius; meeting with Benjamin Netanyahu before receiving an award; being awarded a medal by President Obama (while Steven Spielberg, the director of “Schindler’s List” and also a recipient, looks on alongside Barbra Streisand; performing genially in a concert rehearsal with Billy Joel.

“Itzhak” mixes together these various elements, and more, to tell Perlman’s inspiring story, shifting from one to another in a rather random fashion that leaves the movie feeling, to be a honest, a mite shapeless. That’s an adjective, the film demonstrates, that could never be applied to Perlman’s playing; he molds phrases with absolute precision, while filling them with the emotion you can see on his blissful face as he plays. Those moments alone are worth the price of admission—or, if you prefer to wait a bit, turning on your television to your local PBS channel.