I have a video that is almost 3 hours long. It has 2 tracks of video and 1 audio track. The video tracks are of 2 separate speakers so they cut back and forth depending on who is speaking. When I render just a small section of one of the speakers it is all fine. When I render the whole thing, 1 video track is not aligned with the audio. And what's strange is that it does it intermittently. In some sections the speaker's video and audio is aligned fine and in others it's not. As I said, I've rendered out just those sections where it's not aligned properly as separate clips and when I do that it's synced fine. What could be going on here? Thanks.