From official support, it's clearly that Plex can direct play video in the following formats:
1. MP4 container
Video Encoding: H.264, H.265 (HEVC), mpeg4, VC-1
Audio Encoding: AAC, AC3, EAC3, MP3
2. MKV container
Video Encoding: H.264, H.265 (HEVC), mpeg4, VC-1
Audio Encoding: AAC, AC3, ALAC, FLAC, MP3
MakeMKV is a nice choice to rip your home DVD to MKV format. But HandBrake owns more outputs and supports HEVC well. Many other mainstream free DVD ripper can also help you finish the job with clearer UI, like WinX DVD Ripper and Freemake Video Converter.... Just choose what suits you most
