It's unfortunate that so many video programs default to drop frame when you initialize their preferences. Well, if you attempted to play a 30fps animation through a video card, which has no choice but to run at 29.97fps, one of two things might happen-and both are bad. The alternative is dropped frames-even worse. One possibility is that it will slow your movie down from 30fps to 29.97fps, therefore taking longer to play back. You would fall one frame out of sync every 33.33 seconds, or almost two frames a minute.
Most people can detect two or more frames of slippage in supposedly synced audio and video.
This causes your animation to jump roughly once every 33.33 seconds. You'll run into similar problems if you import properly tagged 29.97fps video as texture maps into your 3D program and work at 30fps. Field of nightmares Another more subtle problem that can creep up when you work inside a motion graphics program is field slippage. If you render back out at the same rate, and keep the fields aligned, there's no problem because on output you would just be resampling the same lines that originally made up each field. As a result, one field is going to be repeated on output every 16.67 seconds.