Casey Affleck on Monday presented an "unflinching" documentary tracing Joaquin Phoenix's lurch from actor to wannabe rapper in "I'm Still Here" at the Venice film festival.
During some 18 months of shooting, Phoenix "never shied away from letting me see all the different aspects of his personality," Affleck said of his brother-in-law who was nominated for a best supporting actor Oscar for his role in the 2000 hit "Gladiator".
"I owed it to him and to myself to do it as well as I could and to make it as unflinching a look at him as I possibly could," said Affleck, who was also within reach of the same prize for his role in "The Assassination of Jesse James by the Coward Robert Ford."
"Ultimately, the film is a sympathetic portrayal of him," said the 35-year-old Affleck, making his directorial debut.
Phoenix's decision, combined with a disastrous appearance on the David Letterman show last year, fueled speculation that the move was an elaborate hoax, a suspicion that extended to Affleck as he stayed mum during his work on the documentary.
"I can tell you that there is no hoax," Affleck said Monday. "That never entered my consciousness until other people started talking about the movie."
"Everyone is familiar with celebrity meltdown, especially in Hollywood," he said. "This was an opportunity to pull the curtain on one of those moments and see some of the gory details and the misconceptions and how somebody rebounds from that, how they get back on their feet."
Though Phoenix is present in Venice, he opted out of Monday's news conference.
"He's trying to embrace the film, he's not hiding from the movie," Affleck said. "His presence here is at least a gesture that he would like to support the film."
Also Monday, Chinese filmmaker Wang Bing shone a cold light on human suffering at a re-education camp in the windswept Gobi Desert in "The Ditch" at the Venice film festival.
Set in 1960, the film chronicles the conditions facing inmates accused of being right-wing dissidents opposed to China's great socialist experiment, condemned to digging a ditch hundreds of miles long in the dead of winter.
Famine stalks the camp, and soon death is a daily fact.
"It's a film that brings dignity" to those who suffered and not a "denunciation film or a protest film," said the documentarist of his first fiction film.
"We wanted to preserve the memories, be aware of the memories, even painful ones," he said.
As Wang was born in 1967, the events "took place before my birth, so I put in great effort to understand the 1950s and 1960s in China, to understand the historical truth," he said.
Li Xiangnian, herself fresh out of acting school, said she discarded the techniques she had learned to embrace new ones under Wang's direction for her role as a woman who comes to the camp to visit her husband, who had died a week earlier.
"I developed an understanding of interior love, something that never changes no matter the era, the powerful sorrow of a strong woman," she said.
The limits of human endurance are also tested in Polish director Jerzy Skolimowski's "Essential Killing," a late entry in the line-up for the 67th Mostra.
In it, Vincent Gallo plays an American Taliban named Mohammed who is picked up in Afghanistan and "rendered" to Poland, where he escapes into snowbound mountains and kills to survive.
On the run in the snow, Gallo also eats bark and hallucinogenic berries - and even drinks a mother's milk at gunpoint - to survive.
Like Wang, Skolimowski said his film was not political. "I'm trying to use as little as possible of the whole political context," said the veteran director, playwright and actor.
The two films are among 24 competing for the coveted Golden Lion at this year's festival, to be awarded on Saturday, with Gallo also present as the director of "Promises Written in Water" about a young woman with a terminal illness.