OpenCV 3.0.0“配置"失败，ffmpeg 未下载

I get the following error when trying to configure OpenCV using CMAKE on windows:

CMake Warning at cmake/OpenCVUtils.cmake:865 (message):
Download: Local copy of opencv_ffmpeg.dll has invalid MD5 hash:
d41d8cd98f00b204e9800998ecf8427e (expected:
89c783eee1c47bfc733f08334ec2e31c)

Call Stack (most recent call first):
3rdparty/ffmpeg/ffmpeg.cmake:10 (ocv_download)
cmake/OpenCVFindLibsVideo.cmake:193 (include)
CMakeLists.txt:527 (include)


Downloading opencv_ffmpeg.dll...
CMake Error at cmake/OpenCVUtils.cmake:888 (file):
file DOWNLOAD MD5 mismatch

for file: [C:/research/opencv300/sources/3rdparty/ffmpeg/downloads/89c783eee1c47bfc733f08334ec2e31c/opencv_ffmpeg.dll]
expected MD5 sum: [89c783eee1c47bfc733f08334ec2e31c]
actual MD5 sum: [d41d8cd98f00b204e9800998ecf8427e]

Call Stack (most recent call first):
3rdparty/ffmpeg/ffmpeg.cmake:10 (ocv_download)
cmake/OpenCVFindLibsVideo.cmake:193 (include)
CMakeLists.txt:527 (include)


CMake Error at cmake/OpenCVUtils.cmake:892 (message):
Failed to download opencv_ffmpeg.dll.  Status=1;"unsupported protocol"
Call Stack (most recent call first):
3rdparty/ffmpeg/ffmpeg.cmake:10 (ocv_download)
cmake/OpenCVFindLibsVideo.cmake:193 (include)
CMakeLists.txt:527 (include)


Configuring incomplete, errors occurred!

我尝试手动下载 opencv_ffmpeg.dll，但配置过程不起作用.