How does quickplayer implement 240fps playback?

hi, i'm working on video decoding based on ************ framework. We try to display a 240fps video on iphone using AAPLEAGLLayer, but it takes 16 ms, more or less, to render one frame. So the video is displayed in slow-motion. But quiketime player can display this video in regular speed without solw-motion effect. In my opinion, the quicktime player droped 3 frames for every 4 frames, so it actually does a 60fps playback. But my colleage think it does a frame by frame playback, the problem is in the way i render. Does anyone know what does quicktime player actually do when displaying 240fps video?