I've just started using Premiere Pro CS6 (Win 7 64-bit) to edit a video podcast I've been working on. We'd previously been editing on CS5.5, and I was able to set my primary timeline to 23.976fps to match footage from my Canon 60D, and then layer in two video tracks from iPhone 4s shot at 30fps to do a multicam edit.
In CS5.5, the 30fps footage worked seamlessly in the 24p timeline, and once I synced up my video files with the audio track, everything worked well (All audio sources were set to 44.1kHz).
In CS6, the iPhone footage starts falling out of sync as soon as I place it in the timeline. By the end of the 30 minute recording, the video clips are way off from each other. I've tried conforming the iphone clips to 24p, and then time stretching them back down to the original length of the recording, but that isn't helping. I've also tried placing the 30p iPhone clips into a 30p timeline, and they still fall out of sync, so it seems like there might be some kind of bug in the playback codec in Premiere CS6?
The only workaround I've found that works now is to open the iPhone clips up in Quicktime, and export them out to a 24p MP4 file. Importing those converted clips back into Premiere works perfectly, but it adds quite a bit of conversion time to my process pre-editing.
Just wondered if anyone else has been encountering this, or if there are any methods of correcting this from within Premiere?