Cannot capture video from file or camera

I'm trying to use this code with python 3.5.3. I have installed all dependencies but the code won't run. It keeps waiting for a while and exits with the statement " capture failed". The trace back leads me to the line 84  which is as follows:
    ```if ret == False:
                 print("Capture Error")
                  break```

can you please help me solve this issue?
