I was trying to load a video the other day, I struggled for a long time. After a long debugging session, I figured out that 'opencv_ffmpeg_64.dll' was missing. I put the dll in place and everything worked. But even though VideoCapture [[VideoCapture]] couldn't load the dll, there were no warnings to show that it failed. I think it should not be this obscure, the dll loading failure should at least generate a warning.