I filmed a track meet the other day and the some of the results will not be posted online. So I have footage of races with no time result. I filmed from when the the gun went of to when the runner crossed the finish line. I just need to subtract the frames from when they finish, from when the gun goes off. I have tried some online calculators, but they round the answer back to 29.97 fps. So no answer will read xx.29 or higher. I am using iMovie HD, with 29.97 fps. I'm not sure if I'm using drop frames or non-drop frames. Thanks.