编译opencv3.4.1时下载失败的opencv_ffmpeg.dll和opencv_ffmpeg_64.dll,下载链接是这个,可使用迅雷下载https://raw.githubusercontent.com/opencv/opencv_3rdparty/0a0e88972a7ea97708378d0488a65f83e7cc5e69/ffmpeg/opencv_ffmpeg.dll https://raw.githubusercontent.com/opencv/opencv_3rdparty/0a0e88972a7ea97708378d0488a65f83e7cc5e69/ffmpeg