This May, I found myself, along with David Flynn, John Zubryckzi and Andy Bower, standing in front of a group of Japanese students in the lobby of Japanese broadcaster NHK's research labs, talking about Dirac.
We were part of the first ever BBC exhibit in NHK's Open House, a week-long showcase where their research labs present their work to the public and industry. We were showing some of the results we had gained in applying Dirac to NHK's Super Hi-Vision format. This is a project to create a next-generation television standard way beyond HDTV. SHV picture are HUGE – a staggering 8000 by 4000 pixels (although there is a cut-down version of “only” 4000 by 2000 pixels) at 60 frames per second. The main target application for SHV is giant screen displays for sports arenas, but NHK are also looking to broadcast to the home for a truly immersive experience for those who have a free wall. There's only one problem: how to move these enormous pictures around. This is where Dirac comes in.
So the BBC has been experimenting with adapting Dirac to code SHV. In our first experiments, we managed to get excellent picture quality at 128Mb/s, which sounds huge but is equivalent to just 4Mb/s for HDTV. Our target is to get the bit rate down to less than 90 Mb/s. Then it will fit in a single satellite transponder. So far we have managed to get great results with plain vanilla Dirac, but in the future we'll see whether we need to have extensions added to the spec.