How can I create a DVD that displays a random number?

November 1, 2007 4:22 PM

How can I create a DVD that displays a random number?

I'm trying to create a DVD that displays a random number on the screen. My actual project is larger, but all my problems with interactive dvd authoring come down to the lack of a solution for this problem.

I have DVD Studio Pro 4, and I can use variables (GPRMs) to generate and store random numbers, but I have no idea how to display the value of said variable onto the screen. Is there another way to do this? Or if I want random numbers between, say, 1 and 100 do I have to generate all 100 numbers as images and choose between them? That can't be the case, can it?

I know that I could 'record' a series of random numbers and play it back, but I would like to have the random numbers be generated, so that each playback is unique.

Google searches are hindered by an endless amount of guides and books for sale. Does anyone have any prior experience with this? Thank you, hive mind!

posted by suedehead to computers & internet (11 comments total)

Is there a function to poll the time from the DVD player, to use as a seed?
posted by aeschenkarnos at 4:45 PM on November 1, 2007

I think it's impossible, if you mean to play your DVD back through a standard DVD player as a "movie", as it were, consisting of a stream of random numbers (excuse me if I have this wrong). A DVD has narrow functionality. It encodes already existing video and audio streams, which can then be decoded and played out to a screen by the DVD player. You are asking for a DVD and DVD player to do something different, which as far as I can tell they are not designed to do.
posted by londongeezer at 4:48 PM on November 1, 2007

Actually, it *could* be possible, hence the mention of GPRMs.
posted by Deathalicious at 4:58 PM on November 1, 2007

I am pretty sure this should be possible somehow other wise how would the randomness work on sceneit dvds?
posted by DJWeezy at 5:03 PM on November 1, 2007

Here's what I think. Don't make a DVD, make a VCD. Use whatever graphics program you want to to make the tiles for the numbers, however you want them to look. Just about any burning software can make VCD's (heck, jpg mix cd's) from pictures and other movies.

Set it to play, and choose shuffle. Actually, if you get the right DVD player, simply put the jpg's on the disc and choose shuffle and it'll play the "pictures" randomly.

That's what I would do if I needed "mostly" random numbers. Of course, there's no such thing as a truly random number, or at least not practically, I guess it depends on how many digits you need.
posted by TomMelee at 5:14 PM on November 1, 2007

Or if I want random numbers between, say, 1 and 100 do I have to generate all 100 numbers as images and choose between them? That can't be the case, can it?

I'm pretty sure that, yeah, that's the case.
posted by hades at 5:34 PM on November 1, 2007

Although, now that I think about it, maybe you could do something interesting with subtitle streams. But there's no provision for on-the-fly character generation in the DVD spec, that I know of.
posted by hades at 5:37 PM on November 1, 2007

Or if I want random numbers between, say, 1 and 100 do I have to generate all 100 numbers as images and choose between them? That can't be the case, can it?

I'm pretty sure that, yeah, that's the case.

sounds right to me too, but wouldn't you only need 10 images? You know, assuming you can display two at once, and do some basic logic with your random variables.
posted by drjimmy11 at 7:14 PM on November 1, 2007

I don't think it's easily possible to do what you want. As others have said, there's no way of generating images on the fly; DVDs are limited to pre-rendered video & images.

It might be doable with menu cells - 1 per number generated - but I think the limit is 99 cells per menu. You can probably figure a way of extending that a few times by menu switching.

Subtitles / buttons over video? Maybe not; there's a few issues with timing & number of available streams that'd make that difficult.

(Hmmm... can you have more than 1 button over video visible at any time? I think not, but it might be worth checking...)
posted by Pinback at 7:39 PM on November 1, 2007

There are only two ways to display elements on a DVD; via the subtitle track or via stored images/elements.

I think you're going to have to build all the images individually (the dvd spec doesn't permit two simultaneous images.)

What you'd end up doing, is playing a 'story' (a series of specific chapters of content) and then having the dvd randomly go to another story (of our 'random numbers' track.)
posted by filmgeek at 6:02 AM on November 2, 2007

Thanks everyone! I really need two random numbers: a counter that goes up to 1000 (or more) and a single digit number. I guess that means I need 10,000 images or so; I'll look into generating numbers via imagemagick or so. Sigh. Thanks a lot!
posted by suedehead at 5:02 PM on November 11, 2007