Case 1: Four XGA displays

This was an exhibition entitled "Deep Space: between body and cosmos", Zendai Museum of Modern Art, Shanghai, 23 July - 31 August 2006, in collaboration with Hellen Sky and David Franzke. It explores connections between art and science, featuring works resulting from collaborations between scientists and artists. The goal was to have four video images, projected onto three walls and the floor (see diagram below). The content consisted of a large database of movies, the exact movies playing at any one time was under software control. In addition, multiple movies on a single display were overlaid with variable degrees of transparency.

The four displays were achieved with a single graphics card with dual DVI ports, to each was connected a Matrox DualHead2Go box. This provides 4 XGA (1024x768) streams, they each present a double width (2048x768) display to each of the computer ports. The total canvas was 2048x1536 or 4096x768 pixels. The content was driven using two Quartz Composer scripts, each one running fullscreen on one 2048x768 display.

• At any one time up to 12 movies were being played at once, more were hoped for but playback performance was the limiting factor. What movie codecs are optimal for this sort of application?
• How does one measure the bottleneck? For example, between disk, movie decoding, and frame drawing? This certainly seemed like a black art and a hit and miss affair.

Photos

Hardware

Mac G5 (PPC), Quadro FX4500 graphics card (2 x dual link DVI), 2 x Matrox DualHead2Go boxes, 4 x data projectors.