will a dual layer dvd-9 disc play on any standard dvd player?

[DC111]

Hi. Am looking at buying a large dvd collection which is said to be on discs referred to as dual layer dvd-9 format.
I am unsure whether these will play on my basic dvd player or on my xbox 360 or whether only some players are compatible ?
Thanks
Further to Gummy Bears answer (thanks) - does this mean the collection I was lookign to buy is not a proper retail DVD collection - it its on multiple dual layer DVDs does that mean it is somebody burning the copyright material to DVD or is it the case that legitiamte retail DVDS are sometime dual layer ?

 

[gummybearst]

the answer is yes.. if the same dvd player also plays other burned dvd's. i have to specify because most sony dvd players and a few samsungs wont play ANY burned discs, but if the one you have already plays the single layers then the dual layer dvd-9's are a very good investment because they hold 8152mb of data as opposed to a single layer dvd's capacity of only 4475mb.