There are plenty of questions where people essentially want to know how to play their DVDs (How can I play encrypted DVD movies?, Lord of the Rings, Toy Story, another one).
Is there any way to know before you buy a DVD to know if it runs on your system?
Obviously, simply looking at the DVD does not help:
Is there any online service or another way to get to know if you can watch a DVD on your computer before buying it?
edit: Sometimes, Amazon customers give this information if it is not working. But I would also appreciate a "white list" of DVDs that do work.