VideoReader : Could not read file due to an unexpected error. Reason: Unable to initialize the video properties
sudo apt install ubuntu-restricted-extras
Make sure the installed version of MATLAB supports the installed version of CUDA. This is very important. I compiled OpenCV with CUDA9.0 and try to compile a mexFunction calling OpenCV CUDA functions in Matlab R2018b. They this release only supports CUDA9.1 so I rolled back to R2018a.
Reference:
GPU Support by Release