在mac上使用OpenCV时，从yuv420p到bgr24没有加速的colorspace转换。

When trying to acquire a frame from a video file (I've tried several video formats) I am getting an error message "No accelerated colorspace conversion found from yuv420p to bgr24". The exact same code ran perfectly fine on a windows machine and I couldn't get it to run on a mac even after I recompiled and installed FFMPEG and OpenCV. I am using lion for my OS. Any ideas?When trying to acquire a frame from a video fil