What is a VOBU map
 

I heard a couple of my buddies who are avid DVD fans talking about a vobu map on a dvd what the heck is one please help and talk in stupid human talk

In bitstream recording presentation data is organised into Video Object Units. These have a variable size but have also a variable duration. To allow access to any Video Object Unit in the bitstream a housekeeping address table, or VOBU map, is used which is based on pieces (VOBU#n) of the bitstream of constant size per piece. The address table additionally contains for each of these pieces a specific delta duration ( DELTA DUR#n) which indicates the arrival time difference between the last and the first packet contained in a piece. The computation of the target VOBU address includes the following steps: accumulate the delta durations until the given time value is most closely reached towards the target VOBU; the running index of this table entry multiplied by the constant piece size directly results in the address value to be accessed.

That's what I came up with using Google.