ISO files...
I don't play or copy CD's DVD's or Blueray discs and have avoided programs that allow you to save those forms of media to another system. I saw one available for free today on give away of the day dot com.One of my clients is in the business of total home automation where lights, appliances, window shades can be controlled via an iPhone. That includes TV's and sound system throughout the house. He has software that allows him to copy any DVD, including protected ones and migrate those movies to a huge hard drive so the clients total library is accessible and they don't have to flip DVD's to watch movies.
Since I'm avoiding Geekdom, much of that process uses ISO files. A quick read says it's a compressed single file of the contents of data or possibly an operating system. So copying an entire DVD to one ISO file so it can be played directly from the system without having to play the DVD.
Most of the people I know who are deeply into streaming, have Netflix or some other service so they pull whatever video they want via internet to see from a huge library. Unless they have a big collection of movies, they probably bypassed the ISO phase.
I'll probably read a little more for the knowledge as I'm told you can copy an entire Windows operating system to ISO for future retrieval.