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ITU plots third dimension

You think HD needs a lot of bandwidth?

While most of us are still struggling with HD-TV, the International Telecommunications Union has started work on standards for the transmission of 3D TV, as well as Ultra-High-Definition TV.

While home 3D might be on every Christmas list this year, the ITU likes to think ahead, with the Russian Federation pushing hard for standards to be established regarding minimal image and sound requirements, as well as ways in which 3D might be broadcast using existing bandwidth allocations - or not. Also in the pipeline is Ultra-HD, offering resolutions of around 7680×4320 for a true "being there" experience.

3D TV comes in two distinct types, one of which provides a different image for each eye, using goggles, colour filters, or clever technology, to aim the images at the correct eye. The other, known as "wave capture", captures a proper 3D representation of the scene - comprised of voxels rather than pixels - and rendered using some sort of dynamic holographic display, or magic, depending on which is developed sooner.

The ITU doesn't concern itself with mundanities such as how the image might be displayed, but has started considering how to ensure that "First Generation" 3D; based on stereoscopic displays, don't cause the eye fatigue that limits the use of existing 3D systems.

Squeezing a 3D image into the existing terrestrial bandwidth is also under discussion - given the similarity between a pair of stereoscopic images there is plenty of room for compression, and the ITU plans to make the system compatible with existing digital broadcasts, presumably existing TVs will simply display one of the images.

But, according to PolicyTracker, the Japanese ITU-R contingent reckons the best way to reduce any kind of eye fatigue is to up the resolution, and wants to see more focus on standardising UHDTV systems. The BBC was involved in recent trials of UHDTV systems, transmitting video at 7680×4320 from London to Amsterdam via satellite, with 22.2 surround sound played back using three vertical layers of loudspeakers to create an immersive environment that was "so real that viewers almost feel they are present at the scene of the broadcast".

The video for that transmission topped 24Gb/sec, compressed down to 600Mb/sec using MPEG-2 - still impossible for terrestrial transmissions but perfectly practical for satellite where high frequencies and a lack of atmosphere make bandwidth less restrictive.

But 3D can also be bodged; the American digital TV standard (ATSC) includes specifications for additional data to be bundled with the signal for bodging the 2D transmission into 3D, and the 3D@Home consortium reckons there are two million TVs in US homes that are already "3D Ready". Though how attractive such images will be won't be known until someone chooses to broadcast the additional data.

The ITU isn't expecting to finish their research until 2012, by which time the recession should be done and dusted and we'll all be looking to spend money on 3D TVs for our living rooms. So next time you're making out in the back row to Jaws 3D, in your colour-coded specs, at least you won't be doing so in public. ®

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