Is it illegal to rip content from DVDs of public domain movies?
Having/packaging/selling a copy of public domain material is not in of itself illegal, however it *is* illegal to break encryption [1] (say on a region-encoded DVD) under the DMCA. As long as you don’t break any encryption to obtain the copy, you should be good to go. On a related note, did you know that www.archive.org has a wide selection of public domain movies available for download? I would suggest checking there first to save yourself a lot of trouble: http://www.archive.