Bach had given way to Bruce Springsteen on the CD player in the hospital room the night David died. It was 'Born to Run', which Bruce had dedicated to David during his British tour in May: a gesture from one fine humanitarian artist to another.

They had known each other since David and I made our film, 'Heroes', about America's discarded Vietnam veterans; and when they toasted each other after the London concert, it was a high point of David's epic fight to live.

He was a rocker, too: the youthfulness, the faded jeans, the cowboy boots, the hint of Elvis in his hair went with him to Vietnam, Cambodia, East Timor, Burma and other places of upheaval and struggle where he and I spent much of our lives together.

David Munro, aged 55, died last Thursday. When the tumours were found, his courage emerged, like a lion, from his gentle, sunny personality; and these few words are a personal tribute to my dear friend and his unforgettable work. He was my director and partner in crime since 1978, when we made our first documentary, 'Do You Remember Vietnam?'

There is an early sequence in that film of children playing in a street in Saigon; they bob and weave in the monsoon rain, their arms outstretched like the wings of attacking aircraft. A little girl, a peanut seller, runs with them in feigned terror.

David had watched the children from a distance, waiting for the light to turn, then he directed the camera in such a way that their play in the film is both a dance macabre and an expression of human vulnerability against the savagery of great power. Without violence or bloodshed, it is one of the most powerful images of war ever shown.

The following year, we made 'Year Zero: the Silent Death of Cambodia', and on our first day in a ghostly Phnom Penh he wrote in his diary: "I don't know what to do to film what we're seeing, because all we're seeing is silence... No one is going to believe us."

Pol Pot had fallen, and in basements, in petrol stations, there were orphaned, very sick children, whom we tried to help. David steered Gerry Pinches, the cameraman, as he filmed rows of opaque eyes, the tears running down his face. Gerry says David held us all together, and it was true. Under duress, he had the capacity to construct extraordinary sequences that honoured the documentary art, yet never surrendered his compassion, as others do.

Whenever we returned to Phnom Penh, cyclo drivers and one-legged veterans would greet him, remembering some gracious kindness he had shown them, always given with recognition of the heroism of ordinary people.

At times I am asked how I have withstood the emotional perils of having witnessed so much human mayhem and suffering. Part of the answer is that I shared a lot of it with David, whose comradeship was unerring, along with a black humour we bother relished. In planning to film under cover in East Timor, he proposed we go as priests, in full kit. "We can hide the camera under our robes, he said. When I offered that we might find ourselves having to read a Mass in Portuguese, he nodded gravely and it was agreed we would go as travel consultants, with Adventure Tours as our cover.

Once at the border at night, we were stopped by goons of the Indonesian special forces. David greeted a thug-faced officer, offering him the local franchise on Adventure Tours' "inaugural package tour". He even produced a "letter of agreement" and threw in an outrageous figure of $10,000, "profit for you personally". With riches in his dreams, the goon let us go.

David's previous career as an actor (Z Cars, the Orlando children's series, lots of rep) made him master of a straight face which, once we were making our getaway, dissolved into hooting laughter. His bravery shone. In East Timor, as in Burma in similar circumstances, he did much of the camera work himself, never flinching as the lens beckoned danger.

He always had time for young film-makers and was teaching at the National Film School when he fell ill. Looking at their work, it was clear he gave them the gift of the true documentary; he would rail against what he called camcorder television. It was not surprising they took turns beside his hospital bed.

As he fought to live, he was supported by a loving family: his younger sister and brother, Hatty and Tim, to whom he was a hero, and his wife, Layhing, who was a Sandinista in Nicaragua when they met.

Their baby, Natalia, had her first birthday the week he went into hospital. Truan, his son, is 20; Pilar, his step-daughter is 17; and Sharon and Susan, to whom he was previously married, remained his dear friends and were with him near the end.

That was the measure of the man; and I salute him. Turn up the Springsteen please.

Guardian obituary