Most commercial DVDs are encrypted and Handbrake can not rip these without an additional component called libdvdcss. Here's a link to an article explaining how to rip a DVD:
https://www.howtogeek.com/102886/how-to-decrypt-dvds-with-hardbrake-so-you-can-rip-them/Another option for ripping DVDs is DVDShrink. It hasn't been updated in several years. It can not decrypt some of the newer encryption schemes, but it works well for the ones it does support. Available here:
https://www.videohelp.com/software/DVD-ShrinkAviDemux does indeed transcode to other video formats. I was looking under the File menu section and the only option there is Save.