Cinema, film is a collaborative art. If the director has the integrating artistic conception of the film, he still has to assemble his realisation of that ‘vision’ through the many critical disciplines, each an art in its own right, that provide the warp and weft of the finished film. It is easy to see the importance of these different skills: the aesthetic ‘eye’ of the cinematographer; the visual imagination of the Production Designer and the collaborative realisation of that visualisation of the film through the Art Director. Most of all, anyone who loves movies will be aware, consciously or instinctively, of the critical skill of the editor – on whom so much of the meaning, the tone – the ‘grammar’ – of a film depends. No great director entirely delegates editing.

In all of these skills Clint Eastwood is magnificently served in his new film – the sombre, dignified, Changeling. This is not surprising: if directors like Altman liked to work regularly with a certain set of actors, Eastwood, ever the meticulous professional whether as actor or Director, likes technical people he knows. Thus on Changeling - long-term collaborators, Editor Joel Cox; Cinematographer Tom Stern (II); and costume designer Deborah Hopper.

From the outset whispers of ‘Oscar’ have surrounded this film: mostly about Angelina Jolie’s powerful performance as real life Christine Collins, single mom in 1920’s LA, whose son Walter disappears while home alone when telephone switchboard supervisor Christine reluctantly covers for a few hours for a colleague who has called in sick. Jolie serves the film well but curiously it is the extraordinarily authentic-feeling recreation of 1920’s LA on the screen that lingers in the mind’s eye when leaving the cinema.

Two collaborative skills limit a movie before a foot of film is shot: screenplay and casting. Writer J. Michael Staczinski’s background is TV which serves him well in writing for Eastwood’s instinctively cinematically episodic approach to scene and narrative. But notoriously the problem for TV writers is making the narrative stretch beyond the average one hour of TV into the usual 2, or here almost 2½ hours, of the average movie. His biggest problem and Eastwood’s, is an acute artistic paradox: the historically true story upon which Changeling is based, beggars belief and challenges our credulity when a corrupt LAPD, under pressure to recover Walter, passes off as him another boy they have found. This is an inherently incredible fact that neither Staczinski’s screenplay nor in the end, however close he gets, Eastwood’s direction, ever quite swings past our sceptical discomfort.

This is the obverse of the usual cinematic coin: usually we are persuaded to accept fiction as fact, imagination as truth. Here, to release the dramatic power locked within this extraordinary true story, we have to believe in the way Eastwood depicts the characters, so that we can accept the way historical fact determines how he must make them behave. Despite a film of many qualities, many Oscar-worthy, and admirable aspiration, for me he doesn’t quite make it. But that he doesn’t is less interesting than why - and this is where Angelina Jolie comes in.

The second, pre-production limiting skill of movies is the easiest to underestimate. It is the one that we can easily turn into a great parlour game – casting. This is a judgment of some depth. It links the combination of screen persona, acting skill, physical, intellectual and emotional attributes of the actor with the character being cast. And type-casting is the Faustian bargain actors face. Roger Moore by his own admission, is a limited actor but as a certain kind of suave, insouciant light Bond, come detective, come man-about-town he has had a long, lucrative, and yes entertaining career. Actors like Ed Norton, Anthony Hopkins or even Pacino before his film-starry-ness got in the way, appear to have a wide range: other like Cruise, Costner, Hugh Grant are much narrower.

The usual casting challenge is - can he/she play up? Can Cher play a lawyer (Suspect 1987)? Just about. Can Russell Crowe play an intellectual genius (A Beautiful Mind – 2001)? For me – no. But the bigger, more demanding acting challenge is rarer: can the actor play ordinary? Some films are stories of ordinary people, living ordinary lives who find themselves in extraordinary circumstances, without which we would never have heard of them: a book would not have been written, or a film made. This is Changeling. This is Christine Collins. For two main reasons, one good, one bad, Angelina Jolie, for me is miscast (or to be fair - perhaps mis-directed) in Changeling, however good she is, and she is good. The good reason is that whatever else one thinks, Jolie is manifestly a highly intelligent woman and actor. The bad reason is that her ever-increasing starry-ness is making it difficult for us to see past Angelina Jolie to the character. By any standards ordinary she ain’t. None of this is helped much by the fetishising, as with Scarlett Johannsen of those bloody lips on camera.

Jolie’s performance as Mariane Pearl, wife of beheaded US journalist Danny Pearl in A Mighty Heart, was superb, worthy of an Oscar in anyone’s money. It is the difference between the two roles that highlights for me why her performance in Changeling is not. Mariane Pearl fitted Jolie like a glove: passionate, articulate, intelligent, resourceful and politically committed. As Marian Pearl Jolie had to hold nothing back, shaped through her acting talent, she could put everything of herself into the role – and she did. And it was mesmerising.

As Christine Collins Jolie is constantly trying to rein in her articulacy, her intelligence. She has to play ordinary because as a person, irrespective of the star stuff, she can’t be ordinary. Just as Russell Crowe had to play intellectual brilliance because he couldn’t be it. The narrative requires her to be an ordinary mom, transformed by the injustice of circumstances into someone who takes on the establishment, the LAPD, the Politicians and the mental Hospital into which the LAPD throws her to shut her up. But Eastwood doesn’t let this transformation out - though Jolie could have played it, perfectly. The only time Christine comes alive is interestingly when she meets hooker Carol Dexter (the superb Amy Ryan) also swept into the asylum and under the carpet by the LAPD after she complains of being beaten up by a cop ‘client’. Carol, as played by Ryan is real and her story only too credible.

I’m not sure Eastwood is all that good with strong women. Even Hilary Swank’s Maggie Fitzgerald in the excellent Million Dollar Baby has to learn from, submit to the boxing training and teaching of Eastwood’s Frankie Dunn. His Christine Collins becomes a kind of passive, dignified focus for removing corruption, rather than an active agent for change. It is perhaps an aspect of Eastwood’s conservative Republicanism that he attributes corruption to the people with authority in the system, rather than something inherently wrong with the system itself: still less that the system often corrupts the people rather than the other way round.

Certainly there are moving and touching moments in Changeling and anyone parent or not, cannot help but feel moved by Christine’s plight and horrified by what we discover to have been Walter’s experience after going missing. Michael Kelly is very good as Detective Lester Ybarra who against the instructions of his boss Capt J J Jones (Jeffrey Donovan) eventually uncovers the truth behind Walter’s disappearance thus blowing the whistle on the LAPD cover up that foisted a different boy, fantasist Arthur Hutchins, on Collins.

Christine is helped by the anti-corruption campaigning Rev. Gustav Briegleb (John Malkovich looking a bit lost in an under-written role); and Jason Butler Harner is unnervingly effective as Gordon Northcott, the ‘child-catcher’ who abducted him. In my view Eastwood has no feel for directing children and all three main child characters in Changeling, including Eddie Alderson as Northcott’s reluctant helper and child-bait (Sandford Clark) seem stilted and ill at ease.

Eastwood’s approach to directing is meticulous and rigorous. He shows rather than tells his narrative by instinct for image over word, not by aesthetic choice. Emotionally he is a miniaturist, almost forensic in his examination of individual feelings. These are great strengths but their consequence is to make him less effective at large events, the rushing river, ever-changing world of politics, public affairs or military conflict, as Flags of our Fathers amply demonstrates. Yet it is in these social and political forces that the credibility of the Collins story lies, not in her inner emotional life. Newspapers, journalism, even a book or a documentary film are perhaps the best media through which to tell the Christine Collins story. The dramatised, fictionalised treatment, if it were ever to work, I think would need a different director than Eastwood to pull off. That said Changeling is a serious piece of filmmaking well worth seeing.

This one has ‘Oscar candidate’ written on the tin and sadly for the Academy’s reputation, that is seldom a bad strategy. It is just the kind of worthy, socially conscious movie they like to reward. For me, Eastwood and Jolie, both very talented, have done better work. But for the wonderfully evocative recreation of 1920’s LA with its different mores and lovely little touches like the roller-skating telephone supervisors, Changeling is rightly a front-runner for technical awards.