Film buffs may quibble over alterations to the historical record, or the fictional additions its makers have countenanced to ensure their picture will appeal to a larger than niche audience, but even they should enjoy “Hitchcock.” This is a love letter to the great director that turns his effort to make “Psycho” into an inspirational tale of a man who puts himself on the line to buck the establishment—a David-and-Goliath story in which David is a creative giant himself.

Anthony Hopkins, though encased in a fat-suit and wearing lots of facial prosthetics, doesn’t really look an awful lot like Hitch. (Watching him reminds you of Kirk Douglas under reams of plastic in 1963’s “The List of Adrian Messenger.” Despite all the gunk, it’s still obviously the dimple-chinned actor.) Nor does Hopkins sound much like the director, though he certainly emulates the familiar slyly lugubrious tones.) But your eyes and ears adjust fairly quickly, so long as you stop expecting an impersonation and accept it is an impression—a performance that’s suggestive rather than photographic.

That’s also made clear by inventions in the script added to flesh out the character. The most notable are periodic conversations between Hitch and Ed Gein (Michael Wincott), the Wisconsin killer on whom Robert Bloch based the character of Norman Bates, as he encounters roadblocks in making his movie. These totally imaginary episodes are meant to provide some insight into the psychology of the director, who with his passion for discipline and rigor despite a shrewdly playful side, is admittedly a rather opaque personality. But they don’t work terribly well, and come across as intrusive rather than revealing. But while the picture doesn’t ignore darker aspects of Hitchcock’s character (his brusque treatment of Vera Miles, who he felt had squandered the attention he had given to her career, or the peephole through which he—like Norman—peered at Janet Leigh), at least it avoids embracing the Donald Spoto school of character blackening one finds in the HBO Film with Toby Jones as Hitch.

And though Hopkins’ Hitchcock is certainly the driving force in the film, based on Stephen Rebello’s fine book “Alfred Hitchcock and the Making of Psycho,” this is far from a one-man show. John J. McLaughlin’s screenplay is structured as a husband-and-wife story in which Alma Reville, the spouse on whom the director leaned heavily not just for domestic support (though he did), but also for advice on his film projects—which included her expertise in script construction, editing and virtually all the mechanics of the process. Helen Mirren plays her with a steely sense of skill and protectiveness—as well as bemused affection for her often exasperating husband.

But here too there’s an invented aspect to the narrative that’s disconcerting, though understandable in terms of giving the story dramatic momentum. That’s Alma’s relationship with writer Whitfield Cook (Danny Huston), which her husband assumes to be an affair and reacts to with a combination of pain and fear that has its impact on how his directed “Psycho.” The idea, which is further interconnected with those Gein interventions, might make for a more satisfying tale for mainstream audiences, but those familiar with the Hitchcocks’ actual lives might find it not such much instructive as unseemly.

What remains, for those who revere Hitchcock and admire his work, are the aspects of the film that reflect reenactments of the record captured so well in Rebello’s book. Hitch’s choice of such “unsavory” material in an attempt to show that he could do the sort of newly edgy material other filmmakers (like Henri-Georges Clouzot in “Diabolique”) were making new waves with. His decision, when confronted by corporate resistance, to finance the project himself, and make it cheaply with his TV crew. The casting process, the choice of screenwriter Joseph Stefano, the reluctant decision to employ Bernard Herrmann’s masterful music cut for the shower scene, the unique advertising campaign that generated enormous public interest, the puckish battles with the censorship office.

All these and similar bits are the real meat of “Hitchcock,” and a fan of the director is bound to wish that more time was devoted to them than to ghostly appearances by Wincott’s Gein or silkily debonair ones by Huston’s Cook. He might also appreciate a more accurate dramatization of Hitchcock’s response to the public reaction to “Psycho.” The sequence of him “conducting” the audience’s screams as they watch the shower scene, standing outside in the lobby and listening intently, is amusing, but hardly true-to-life. His was a far more confused and complicated attitude, as Rebello documented.

But “Hitchcock” isn’t documentary, it’s only a movie—as Hitchcock himself was accustomed to say. And on that simple basis it’s a good deal of fun. Sacha Gervasi’s direction is more workmanlike than brilliant, but that only shows he’s no Hitchcock either. And he does give Hopkins and Mirren ample opportunity to shine. Scarlett Johansson makes a likeable Leigh and Jessica Biel a properly spunky Miles, and in a very brief turn James D’Arcy is a pretty good Anthony Perkins (though Andrew Garfield would have been still better). Toni Collette as Hitch’s aide, Michael Stuhlbarg as his agent, Kurtwood Smith as a sensitive censor, Ralph Macchio as Stefano, Wallace Langham as Saul Bass and Paul Shackman as Herrmann all have brief but telling moments. It would been fun had Gervasi made a cameo appearance as Hitchcock always did, but unless I’m mistaken it doesn’t happen. Technically the picture is solid if unremarkable, with good period production design (Judy Becker), art direction (Alexander Wei), sets (Thomas J. Machan, Andrew Birdzell and Robert Gould) and costumes (Julie Weiss). Danny Elfman’s music score—he actually redid Herrmann’s for Gus Van Sandt’s none-too-fondly remembered shot-by-shot remake of “Psycho”—is less distinctive than his work often is. But who can compete with Herrmann?

And the same, of course, can be said of the movie. “Hitchcock” is frankly no “Psycho.” But on its own terms it’s an engaging tribute to that masterpiece, especially worthwhile in that it brings Reville to the foreground. And if it sends audiences back to watch—or watch again—the film that inspired it, all the better.