Video preloading in AV Video Players

I am currently working on an app wich will preload 3 AVplayers wich are in an array. With preloading I mean, that the first 30 seconds of the video should get loaded before the video gets displayed on the screen. I decided to do the preloading by iterating through the array, playing all players until they are at 30 seconds. As the players are in an array, there is still a pointer wich references to the memory location on wich the video buffer and the already played video is saved. Is it true, that with that solution, the first 30 seconds won't be loaded when I start the players again at 0 seconds, because I already loaded the first 30 seconds.