DVD Studio Pro

Each year at ultralab we have embarked on a digital creativity project with young people. This year we went worldwide and invited children to make short videos and animations. Some of this has subsequently appeared on BBC2 (more on that another time), and all of it goes onto a DVD which we author at the ‘lab.

This is always a tremendously intensive time for us. This year, Matt did the video editing, Neil did the sound work, Alex did the graphic design and I put the discs together (with lots of help again from Matt… and Alex).

One of the features we wanted was a video jukebox, where a viewer could select any clip in any order and build a play list. We restricted it to eight clips, but it was a fairly complex bit of scripting that achieved this for us. Huge, huge thanks to Alex Blanc for working through the maths involved and entertaining the idea that ‘bit-shifting’ in 16 bit registers was do-able! Previously I have only seen this feature done theoretically and only with eight clips available as a maximum. We had twenty four clips to select from…

Of course, inspiration has to arrive from somewhere, and in my case it came from Alex Alexzander who is based over in LA. Our contact via the various DVD forums on the web has grown over the last year or so, and it was he who first suggested it could be done, and wrote an article and shared sample scripts to get it all going. Thanks Alex!

To cut a long story short, the viewer can select a single clip, or keep going until eight are chosen. Playback will then commence and when done return you to the jukebox menu. This involved a script for filling the registers with the selected clip numbers, a script to clear some of the registers to use in the next bit, a script to extract the clip numbers from the registers in sequence, a script to control which clip played and a script to clear all of the registers ready to start again. The register stuffing and unstuffing were the two biggest scripts – they started off as a massive 40 line each job – Alex brilliantly reduced them to just about nine lines. If ever I get a chance, I’ll post them, and add a tutorial so that you can apply them yourself. You’ll need two menus, a shedload of chapters on a track for your DVD and the ability to think through the logic of where these scripts take you. Other than that, any project you do can use these methods!

Thanks again to Alex, Matt and Neil – let’s hope the tapes we sent to replication come back with fully working discs!