Monday, September 22, 2008

Another data point on immersion

A while ago I estimated the bandwidth required for 3-D Imax at 13GB/s, uncompressed. Today I got the latest newsletter from the California Academy of Sciences bragging about the new and improved Morrison Planetarium. They say this bad boy can blast 300 million pixels per second onto its hemispherical screen. At 32 bits per pixel, that's about 1.2GB/s, or about a tenth of my IMAX estimate (I think I used 32 bits per pixel to ensure a conservative estimate of the bandwidth required. 24 ought to be good enough).

Take out a factor of two since 3-D requires two images and assume that the frame rate is 24 frames/s in both cases. The remaining difference is down to spatial resolution. IMAX is about 10K by 7k, or 70 megapixels, so the Morrison is more like 14 megapixels. In the earlier article I guessed that the 13GB/s could probably be compressed down to 1GB/s, partly because the two 3-D images would be largely redundant. Planetarium-level 2-D video would also compress, but not quite as much. Bottom line, you're still looking at gigabits per second to be able to handle this stuff.

The Academy also claims that the panetarium would hold 2,402,494,700 M&Ms, but I'm skeptical about either the volume of an M&M or the planetarium, much less both, being known to a part in 10 million.

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