For Audio CDs you want to rip it lossless with something that support AccurateRip so you can be sure that others made the same copy byte-to-byte. Fortunately there are several options https://wiki.hydrogenaud.io/index.php?title=AccurateRip#Soft...

For DVDs you can use the infamous DVD Decrypter to make ISO files https://en.wikipedia.org/wiki/DVD_Decrypter

or MakeMKV which straight copies the MPEG2 files (.vob) into a nice MKV container https://www.makemkv.com/