Enhanced Video Object, also known as Enhanced VOB or EVO, is a container format for HD DVD video media. It contains the actual digital video, digital audio, subtitle and DVD menu contents in stream form. It is an extension to VOB. It can contain video encoded in H.264/MPEG-4 AVC, VC-1, or H.262/MPEG-2 Part 2 and audio encoded in AC-3, E-AC-3, Dolby TrueHD, DTS, DTS-HD, PCM, and MPEG-2 Part 3.
There are a few consumer software solutions that can play EVO files, such as PowerDVD, WinDVD for Windows and FFmpeg for Linux (unprotected EVO only), and the cross platform VLC Player.
References
Enhanced VOB Wikipedia(Text) CC BY-SA