DVD Studio Pro 3: In the Studio

Testing and Debugging Scripts

Simulating DVDs with scripts is vital. With all the fun and extra features that scripts allow, you can add a lot of complexity to your projects, so you want to check your scripts thoroughly. The Simulator is the quickest route to verifying (or fixing!) the flow of your scripts. You certainly can burn discs and test them in a player, but that adds both time and money, so it's best to get comfortable with the Simulator.

Most bugs come in the form of forgotten states—for instance, you set the current audio track for one feature and forget to change it back to the default. Fortunately, the depth of DVD scripts is limited, so you can verify that your disc works as intended—it just takes a bit of time and patience.

As an example, our previous project with the Play All button left out a tiny detail. What happens if you choose the play-all option and then come back to the menu to repeat one segment? You never wrote any code to "unset" the Play All variable. After you go through the play-all option once, every clip you play after that will think the disc is in play-all mode. That wasn't obvious (at least to some of us) as we were setting up the project. But it became very obvious once we simulated the disc and played around with the menu.

So, how did we discover the bug? Regrettably, it wasn't via a very scientific method. We played several of the individual clips and they all worked properly. We tried the Play All button and it worked great, too. We were on a ...