Menu Overlay Question

[pbombach]

In examining the structure of a commericial DVD, I noticed that all the menus are contained in the first vob of a particular titleset (literally VTS_04_0.VOB). However, I don't see any place where the menu overlay is placed, i.e. where is the image to change the button selections to be displayed highlighted. Can anyone tell me where that information is stored? The cursor is also shown as a little hand. Where is that information stored?

Thanks.

Paul Bombach
pbombach@umich.edu

[VidHack]

Welcome to the wonderful world of DVD structure.

You need to download VOBedit. Then open the same menu VOB. The buttons are imbedded in the video stream, if your technically minded goto ......
http://mpucoder.kewlhair.com

Its all there. Enjoy.

VidHack

[pbombach]

VidHack,

Thanks for the reply! To the newly initiated, wonderful world of DVD structure seems a little daunting.

I have downloaded VOBEdit. I actually used it to demux the VOB original VOB into it's Cell-IDs. That's where I learned that the entire menu structure is contained in the VTS*_0.VOB. What I don't understand though is where the selection highlighting comes from, since all the menus that are contained in this VOB are in an unselected state. How does the DVD player know to color the play movie selection green when it is selected. I didn't see it in the individual cells from the original VOB.

Thanks.

Paul Bombach
pbombach@umich.edu

[pbombach]

Is it perhaps contained in the subpicture data?

Paul Bombach
pbombach@umich.edu

[VidHack]

Hello again,

To get you going....Open up the menu VOB, check the BUTTONS box, then scroll down the slider on the right. You will see the button X/Y locations that appear on the screen. Then open the titleset.ifo (Probably VTS_01_1.ifo) in IFOedit, check out the IFO info, it holds the subpicture color info. Its a Table, dont have time to go into details right now...Sorry.. but its all there. Its a combination of using the .IFO and the actual menu video. Have fun.

VidHack

[mpucoder]

The subpicture contains the visual shape of the buttons. The logical shape, which determines when the cursor is over a button, is contained in the associated NAV pack, as are the colors for selected and activated (the normal colors are contained in the subpicture command sequence). But, these colors refer to a Color LookUp Table (CLUT) located in the associated PGC (which is in the ifo file). The NAV pack also contains a lot of information about each button, such as which button is next if the user presses left, right, up, or down, what command to execute, if selecting a button automatically executes it, how long to wait for the user, etc.

2 pages of interest http://mpucoder.kewlhair.com/DVD/pci_pkt.html
and http://mpucoder.kewlhair.com/DVD/spu.html