After I edited a video and rendered it, the video was choppy at parts. I went back and checked the clips on the timeline, but they were normal. I also rendered the video about 3 times with the same result, in case of other applications interfering. Any suggestions? It's probably something simple.

If you really want to see the problem, here's a link to the video: (the problems occur about 2 minutes and 17 seconds in to the video. I know the video's not pro, haha.)