I added the pitch effect to an audio clip and once I viewed it on the playback, the video was super choppy and low frame rate. All the tracks were like that until the audio clip that I added the effect to, ended. I dont think its changing the video itself because the time line is still the same. I also dont think its the clip thats causing this problem because it works with other audio effects just fine. Im in a big hurry and I need an answer now. I found some other people are having the same problem as me with different effects.