The boy's father, Park Jong-dae, provided it Thursday to The Associated Press, saying he wanted to show the world the conditions aboard the Sewol as it sank. He earlier released it to select South Korean media.
More than 300 people are dead or missing in the disaster, which has plunged South Korea into mourning and touched off anger and shame. About 220 bodies, mostly from inside the submerged vessel, have been recovered. More than 80 percent of the victims were students from a high school in Ansan, south of Seoul, on their way to the tourist island of Jeju for a school trip.
The group of teens in Park Su-hyeon's video alternated between bluster, attempts at humor and unmistakable fear.
Only one could be seen wearing a life jacket at the beginning of the clips, which started at 8:52 a.m. and ended, with a small break between them, at 9:09 a.m., when everyone appeared to be wearing them.
Some of the students struggled as they tried to buckle the life jackets. As the listing worsened, they joked about "final commemorative pictures" and "defying gravity" by trying to walk on the walls.
"It's like we're becoming the Titanic," one student said.
At 8:53 a.m., less than two minutes into the video and two minutes before a crew member on the bridge made the ferry's first distress call, one student said: "Am I really going to die?"
At the start the video, a message blared from the ferry's loudspeakers: "Don't move away from your places and brace for any possible accidents."
In subsequent announcements, passengers were again told to stay put, even as some questioned whether they should flee.
The last message from the bridge came at 9:08: "We're again announcing: For passengers who can wear life vests, please wear them now. Never move away from your places."
That warning came eight minutes after a Sewol crew member told a marine traffic official, "The body of the ship has tilted, and it's impossible to move," according to a transcript of communications with the ferry.
After the passengers were ordered to stay in their cabins, Capt. Lee Joon-seok took at least a half-hour to order an evacuation. It is unclear whether that order was ever relayed to passengers. Lee has said he delayed the evacuation because of worries about sending passengers into cold waters and fast currents before rescuers arrived.
Lee could be seen in a separate video released by the coast guard leaping from the ferry in his underwear onto a rescue boat while many passengers were still in the sinking ship.
He and 14 other crew members responsible for the ferry's navigation have been detained on suspicion of negligence and abandoning people in need. Prosecutors are investigating whether stability issues related to too much cargo or a redesign that added more cabins to the ship contributed to the sinking.
As Park Su-hyeon's video continued, students asked whether the ship will sink and where their teachers are. "What's the captain doing?"
After the students talked about being on the news and posting about the excitement later on Facebook, the fear in the cabin grew. Some said they felt dizzy, that their legs were shaking. One student was seen walking with his hands braced against the wall for balance as the vessel continued listing, making it increasingly difficult to move.
"I'm really scared," a student said.
"Is it really sinking?" another asked. "Wow, they're giving us life vests."
"I'm getting out of here," one said. "Me too, me too," says another.
A student says: "We have to survive now."
At one point, the teens were heard offering their last words to their relatives. Some warned their siblings not to take school trips unless they wanted to end up like them.
"We're all finished. I have to leave some farewell words before I die," one student said.
"Mom, I love you," another said.