Director Cao Jinling (top) and actress Zhou Xun, who sings the theme song of the film, attend the premiere of Days and Nights in Wuhan. CHINA DAILY

"All of our crew were moved by the video material. In the footage, you can see the benevolence of doctors, the dedication of medical staff despite the risk of getting infected, and the tenacious vitality of patients fighting the virus," says Li.

"More importantly, we can see the respect for life. During the lockdown, patients were all treated with care, whether a man in his 80s or a pregnant woman or a newborn baby. You can see the weakest patients being tenderly cared for," Li says about what led her to produce the documentary.

With a wish to showcase how this unprecedented disaster brought out the best in the Chinese people and united them to fight together, Li invited director Cao Jinling to helm the film, with the crew spending around five months focusing on the job in a studio on the outskirts of Beijing.

Having earlier worked as a police officer, Cao had shifted to the film industry after writing the script for South Korean director Kwak Jaeyoung's 2014 film, Meet Miss Anxiety. After earning a doctorate from the Central Academy of Drama, Cao was handling postproduction work of her directorial debut, Anima, when she received Li's invitation.

Despite keeping a close eye on the news about the outbreak back then, Cao says she had never thought she would direct such a film as the theme was "too serious and heavy "for her.

A part of the preparation for the film was done before Cao joined the project in April. Her initial challenge was that the original footage came in various formats after being shot.

"When the camera crew were shooting in hospital wards, they had to compete against time. They had to put on thick protective outfits as well as use layers of plastic to entirely cover the cameras to avoid being infected, but that affected the equipment's ability to shoot images clearly," Cao says.

Despite the footage issues, the director says she believes the authentic scenes captured during the most difficult time in Wuhan have the power to draw the audience.

"The reality and emotions are more important than techniques," Cao says, adding that it's a lesson she's learned from the renowned cinematographer Mark Lee Pingbing, an award winner at the Berlin film festival.

In October, Cao alongside the film's crew traveled to Wuhan in an attempt to seek new content as a backup for the almost-finished film. She was surprised to see the city, with a population of 11 million, had recovered and a normalcy was back.

"Although there is no way to avoid uncertainty and unhappiness in life, it's important to keep on going with courage, hope and love. That is the message our film wants to convey in this unusual time when the world is still fighting the pandemic," she adds.

Contact the writer at xufan@chinadaily.com.cn