Transcoding a DVD at high settings will be indistinguishable from the original, and will take half the space. For example, when I download shows from my TiVo, they're MPEG 2 files, similar to a DVD. I transcode to H264 into an MKV container. This format plays natively on my AppleTV. And at good settings, I lose nothing visible while getting a video file same size or smaller. But, to rip ISO, I think you have to buy AnyDVD. For this to be free, MakeMKV is the way to go. Which has you either making a folder backup or extracting to MKV. For your immediate problem of freeing up space in your apartment without losing favorite movies, you can try ripping a DVD or two with MakeMKV and see how it goes. If it's an OK solution for you, then rip your favorite couple dozen DVDs, and put them in storage. That solves the next six months concern, without spending much money or trying to boil the ocean to solve all video needs for the next five years.