This screening on the final day of 2017's Oxford International Film Festival starts with a selection of shorts, before the main feature One Note at a Time.

First, Pickup immerses us in the life of a well-to-do mother (Mandy Evans), dissatisfied with her lot and swiping on Tinder as her husband lies two feet away. The cinematography gets the surface sheen of this life across, and as she waits for her hook-up Evans' glassy stare is phone-screen-like, remaining morally neutral and concealing depths. But I'm left wanting more of the depths, or something unexpected. Extended music video Ever Dimming Room, directed by Min Reid, follows songwriter Derrick Boudwin as he speaks about his degenerative eye disease and its inevitable progress. His honesty is moving, and I'm hooked in by a shot that pulls up from a portrait-like close-up of Boudwin to suddenly reveal Oxford's skyline, a feast for receptive eyes. Some more subtlety in the score and greyed colour palette would be good, but I can see the piece signalling the concerns of our main feature.

And what a main feature it is. (Since going to press, it's taken three OXIFF awards, more than any other OXIFF entry, including Film of the Festival- Ed.) Sometimes, films really take you by surprise. Director/Producer Renee Edwards has crafted a documentary about the embattled tradition of New Orleans' musicians, and their struggle for continued habitation and survival after their careers have been made barely tenable by natural disaster, poor flood defences and political machinations. Now, of course I'd be interested: a close-up look at musicians such as Dr. John; an artful look at a waning culture as in Embrace of the Serpent; all the vibrancy, voodoo, Dixieland and drama of N'Awlinz. Somehow, by looking at a city ravaged by and recovering from Hurricane Katrina without focusing on the Storm Herself, this lovingly and masterfully assembled film swept me away.

So the camera is trained, instead, on a city in recovery - an optimistic stance in the face of death and displacement. The humanitarian thread tying these colourful and sanguine scenes together is the work of the NOMC, a clinic specifically for musicians, many of whom have no health insurance and fall financially between qualifying for Medicaid and Obamacare. Dedicated and dependent on donations, Bethany and Johann Bultman are the pioneers behind the NOMC who attract artists from this treacherous valley, offering them treatment and services which have educated and saved the lives of many professional musicians. They're mildly eccentric, passionate and realistic about how US conservative policies could drastically shrink the extent of their good work.

In close-up, we see Dr. John wiping away a tear after his long-serving drummer succumbs to illness. Walter Payton, Jr. sings at the Louisiana Music Factory, doing some comedy high-kicks during an instrumental, full of fun. Wardell Quezergue finally hears a mixdown of the classical piece he'd been working on, reclining in a hospital bed and saying "put it out" as if this command is his last. Shelton 'Shakespear' Alexander delivers his spoken word opus as the Second Line Parade passes vivaciously by. These illustrations of pragmatism v. creativity, music v. mortality, accrue a great emotional weight - and some interviews and performances are the last recorded by the artists here immortalised. In New Orleans, they don't go gentle into that good night.

Without getting too spoiler-tastic, it unexpectedly evokes Rogue One - more death than you might foresee - but we're not assured it'll be followed by A New Hope. Edwards, who has been a film editor on Panorama since 2002, is saddened by the lack of care flowing from the US government to this city, to which she has a close familial connection. She avoids polemic, she never appears on camera, and she allows the unique characters and potent grooves to make their own case. Ray Russell's award-winning score is also remarkable, cohering with the rootsy musical surroundings but tastefully staying sub-radar. Having worked also on Lost in La Mancha, an award-winning account of Terry Gilliam's storm- and illness-beset attempt to make his Don Quixote, Edwards has seen the battle of 'Art against the Elements' before. Nine years in the making, labour of love One Note at a Time may've come up against logistical issues of its own. In it Renee Edwards demonstrates the heart, the vision and the breathtaking editorial discipline to make lasting art out of that same struggle.