Original sentence: Analogous to MPEG-2 Program streaM, VOB file can contain MPEG-2 Part 2 or MPEG-1 Part 2 video, MPEG-1 Audio Layer II or MPEG-2 Audio Layer II audio, but usage of these compression formats in VOB file has some restrictions in comparison to MPEG-2 Program stream.If the copied undecrypteD VOB files are opened in a player, they will request the keys from the DVD-ROM drive and will fail
Edited sentence: Analogous to MPEG-2 Program stream, VOB file can contain MPEG-2 Part 2 or MPEG-1 Part 2 video, MPEG-1 Audio Layer II or MPEG-2 Audio Layer II audio, but usage of these compression formats in VOB file has some restrictions in comparison to MPEG-2 Program stream.If the copied undecrypted VOB files are opened in a player, they will request the keys from the DVD-ROM drive and will fail