How to know if the file was found?

I am trying to load a movie like this:

movie.loadMovie("D:\downloads\VID_20160603_205751.mp4");

And i’m stuck on this error:

setupError occured while playing or pausing or opening the file
[ error ] ofDirectShowPlayer: Cannot load video of this file type. Make sure you have codecs installed on your system. OF recommends the free K-Lite Codec pack.

I have a topic about that here:

The thing is, I get the same error with an incorrect path:
movie.loadMovie("D:\some_path_that_doesnt_exist\a_non_existing_vid.mp4");

So how can I know if it is the codec or the file not being found?

I’m not sure how to answer your question directly, but you can try putting a file that you know works at the path and see if that will load. There is one in
examples>video>videoPlayerExample>bin>data>movies that should work

Also try running the example project on your computer first to be sure the codes are installed correctly.

Best,
Rob