Programming question

[dbernat32]

I am new to programming DVDs with advanced features. I have, however, authored several simple dvds with Maestro and Scenarist.

My question is thus:

How would I go about programming dynamically activating subtitles.
i.e. At some point (a certain time in the video, not necessarily at a chapter stop) the dvd player should check if a certain subtitle stream is active, if yes, do nothing. If not, activate the subtitle for a certain period of time and then turn it off again. This sequence would be repeat at each point in the movie where the subtitles needed to be activated dynamically.

As a said, I am new to advanced programming and have no idea where to begin.
Any help would be appreciated.

--David
dbernat32@aol.com


P.S. I already know I could use two subtitle streams, one with subtitles throughout the movie and one with them just at certain points. I would, however, like to learn how to use one stream dynamically.

[oddyseus]

Never attempted such a task but I can offer u my thoughts.

U may use button over video that autoactions and that will call a command sequence to check what u need.

I will surely watch over this thread. Any pro out there willing to help?

[McPoodle]

The DVD Spec does not allow control over individual subtitles. Therefore, you will have to have seperate streams (I assume you're trying something along the lines of English dialog/English translation, right?). You can use programming to switch subtitle streams. For example, you can read SPRM18 (the preferred subtitle language) and SPRM16 (the preferred audio language) and use this information to figure out which stream to default to. The values for these two registers are not in the DVDMaestro manual. They are in table A.24 of DVD Demystified by Jim Taylor, or you can go to this page (http://www.geocities.com/mcpoodle43/DVDMaestro/language_codes.html) that I put up.

If you want to see how to go about this kind of programming in greater detail, take a look at this (http://forum.doom9.org/showthread.php?s=&threadid=40415) thread.

[dbernat32]

McPoodle,

Thanks for you reply, but if you read the "P.S." I said I already know I can do it with two subtitle streams i.e. "StarWars:AofC". I want to do the English dialog/English translation with only ONE subtitle stream i.e. "Ronin R1".

To that end I'll make the question more straight forward.
How can I run commands when I reach a certain time index in my movie?
This certain time will NOT necessarily be at a chapter point.

I am open to any suggestions.
Note that I am new to advanced DVD authoring. I have never done things like invisible buttons or fake chapter points or stuff like that.

[oddyseus]

Why don't u start now with fake chapter pointers? U can define a chapter pointer that wont be accounted for in the chapters menu and u will stick a command sequence on it that will switch the streams as needed.

However this is much easier in Scenarist where u can add a pre and a post command in the required cell that will change streams back and forth as needed.