New Post: Force frame rate

My conversions work 95% of the time (MKV high quality) but occasionally the frame rate of the resulting file is 59.9 instead of 29.9 and then these files are awful on my AppleTV. Is there anyway to force the frame rate to 29.997? My guess is to put this option (-r=29.997) on the ffmpeg-video= options line but I've never seen anyone else use this so didn't know if anyone could help.

Thanks