The accident was captured by people in the crowd at the electronic music festival in Esteio near the southern city of Porto Alegre in Brazil.
The fan-caught footage shows the moment when the stage buckles and falls over while a crowd of around 5,000 people watched.
Freitas was performing when the structure was brought down and he was rushed to the hospital with head injuries but died soon after arrival.
The organizers have said severe weather conditions were responsible for causing the stage collapse.
The music festival went ahead despite adverse weather warnings from authorities.
Local Civil Defense coordinator Alexandre Camboa said: "The forecast for Sunday afternoon was gale-force winds, and torrential rain."
Atmosphere Festival has issued an official statement (originally in Portuguese):
"We always cherish the security of our audience, following all the processes, reports and authorizations requested by the local authorities. And to our audience we will keep them informed of all our actions to keep the truth about the facts that have occurred. We're sorry, we lost a friend, an artist. Our priority is to assist the wounded and their families. We thank the military brigade and the fire department for all assistance."Sergio Bandoca, one of the people in charge of the exhibition centre where the rave took place, said:
"It was madness. The scale of the tragedy could have been far worse. Things were flying all over the place. There was panic."
The atmosphere Gods were not happy...