Well, this is a delicate issue, since the problem is not always solved as we will see below, but many times we can solve it ourselves. The DVD player of our Mac (if any), may be affected by some other problem, one of them is the one we expose in this article.
This is not the absolute solution, but as a possible solution to the error of the famous pixels or squares that appear on the screen when we want to see an original DVD, on our Mac, it can work.
It may be that this error of squares that scroll on your screen or tremors of the image, don't just happen to you when you try to play a DVD original in the CD's slot and you have the same problem when you use any movie player on the Mac, that's when we can apply this solution that possibly solves our problem.
It is in these situations, when we can go "crazy" looking for the possible error on the network, looking to see if we find the solution without having to pass the SAT Apple, if we are under warranty it does not bother us so much, but in the case of being out of it, it can become an economic problem.
To delete this folder, which is hidden, we open Terminal, in Applications, Utilities and write this line of text:
rm rf ~/.dvdcss
With this operation what we do is delete the folder that is hidden from the DVD, but don't worry, OS X will recreate the deleted folder instantly and possibly we have solved our problem with the viewing of DVDs.
To check if what is done works, we just have to relaunch the DVD or player vlc and if it works well, great, in the case that it does not work we will have to go through the Apple SAT if we want to have this function.
More information - A Tip for Mac, Start / End
Source - cnet