Suggestions, if not found, replace '_' with ' '.
The scanning engine makes complete abstraction of all the punctuation marks.
That way the user might be able to better understand your naming convention.
There's no special naming convention. The scanning engine starts with the first word and continues until it finds the longest string that matches a movie title. If several movies are matching that longest string, the program looks if the file name includes the movie year after the movie title. I there's no year and some words were discarded beyond the longest string, those words may help pick up the right movie. Otherwise, the program simply picks up the movie with the more votes on IMDb.
I have 4 versions of Robin Hood but your app matches with the latest version. I have not been able to find what the exact movie name your app is looking for so after making a dozen guesses I give up.
It looks like a case where adding the year could help.
If you find absolutely no way to associate the right movie, you can mark it as "unrecognized" and then associate it manually by going to the movie and clicking the "play" icon. But there should be very few cases where it's necessary.
Please give me some examples of file names where the movie is in our database but you can't make the associate correctly.