I recently shot a series of interviews for a documentary using a Canon 7D. The video was recorded at 23.98 fps.
The audio was recorded on a separate device (a Tascam DR-100), with a boom mic setup. We recorded the audio (wav) at 16-bit Integer (Little Endian) 48.000kHz.
I have used compressor to convert my H.264 video clips to Apple ProRes 422, but have kept the original frame rate (23.98 fps).
I then imported the clips to final cut pro (version 6.0.6) with a timeline sequence set up for 23.98 fps. The problem I am having is when I sync up the sound with the picture, it starts out sync but slowly (over a few minutes) the audio gradually over takes the video.
I have tried various solutions, cinema tools conversions of the video from 23.98 fps to 24 fps, slowing down the video in fcp to 99.9% (which did work on some clips) or recompressing footage to different frame rates. It seems that none of these solutions works very consistently.
its actually 23.976 fps. also if that doesn't work, sync up the audio to the original with premiere's rate stretch tool to the waveform of obvious silibants. (The farther away the 2 wavecrests you choose, the more accurate the sync). It's possible that the Tascam DR-100 is not timecode accurate.