Playing a .CDR file from Hard Drive

Hi, I have copied a DVD to my hard drive using Disk Utility. I did this as a back up should the DVD become damaged or lost. I can make a DVD out of it so all is well. I however wish to be able to watch the DVD directly from the Hard Drive ie from the .CDR file.
Is this possible? Advice welcomed. Alternative approaches welcomed if the above is not feasible.
Thanks in advance.
Phil