I have some video that was shot on two different cameras and then audio that was recorded externally. I'm working in Premier Pro CS6, by the way. My problem is, for some reason the video and audio won't sync up after some time. They start off perfectly, and then as time progresses the audio ends up being significantly ahead and progressively more and more as it goes on. Now, I know the audio is absolutely correct, I am a professional audio engineer for over 15 years, on that side of the fence I know what I am doing. The audio is from a live drum performance we recorded at my studio, while filming with the two cameras (a GoPro and a Samsung S5 phone). That recorded audio was performed to the album's backing tracks and the click (metronome) track as well - it lines up exactly with the album version of the same song and is exactly the same length. So that leaves the video.
Both were shot 1920x1080, the GoPro at 59.94fps which I converted to 29.97fps, and the Samsung was filmed at 29.97fps already. Those two video clips sync up to each other just fine. So, both video files do the same thing with the audio track.
When I imported the video files I had Premier change the sequence's settings to match the video files. Beyond that, I have no idea what I can do, or may have missed, that would fix or cause this issue to happen. I am hoping someone here knows what is going on.
I have done this same type of video project a few times before and never had any problems, but I'm by no means experienced or knowledgeable on video production. My "skills" are limited to what I have learned from youtube tutorials as I needed to know something I couldn't figure out on my own. So I'm in the dark here :(