How to rip a Blu-ray using the program MakeMKV with the intention of ultimately converting the file to DCP for viewing in cinema. Process works just the same for making digital copies of your discs for at-home viewing or archival purposes.
Alternatively, you can rip your DVDs to MKV/MP4/MOV/H.264 by using this free program: https://bit.ly/3BW0iA3