Soon after the ferry began to tilt, there was nervous laughter, jokes about the Titanic and talk of selfies and Facebook posts from the doomed high school students huddled below deck, some of whom sang Celine Dion's Titanic theme My Heart Will Go On as their ship began to sink,

But the lighthearted atmosphere soon turned serious as the listing worsened. Fear began building, and one student asked, "Am I really going to die?"

The shaky video - at times poignant and heartbreaking as the teens said last words to their loved ones - was found on the cellphone belonging to 17-year-old Park Su-hyeon when his body was recovered after the disaster on the morning of April 16 off South Korea.

The boy's father, Park Jong-dae, released it to the media, saying he wanted to show the world the conditions aboard the Sewol as it sank. Information such as video can be recovered from micro SD cards in cellphones even if the device is submerged.

More than 300 people are dead or missing in the disaster, which has plunged South Korea into mourning and touched off anger and shame. The group of teens in Park Su-hyeon's video alternated between bluster, attempts at humor and unmistakable fear.

Some of the students struggled as they tried to buckle their life jackets. As the listing worsened, they joked about "final commemorative pictures" and "defying gravity" by trying to walk on the walls.