Production Technology Seminar 2009 - EBU Technical

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the consumer could first select if they wanted to view in 720P or in 1080i. Naturally if that happened
1080P50 would have reached the consumer already as the transport stream would have supported it.
This matter of considering the short, medium and long term evolution to 3DTV can be given thought
today before defacto or knee jerk standards enter the market place and shift consumption away from
FTA channels. Effectively this kind of option is possible with 3D providing a good level of backwards and
forwards compatibility and the model to evolve (to the pace felt comfortable) with 3D broadcasting.
HDTV required both new displays and set top boxes. This was issue because of the considerable
change from standard definition components and the attendant costs. The model put forward by
TDVision will still require either a box firmware change or a new STB. However, many of the existing
silicon available today is compatible with this 3D broadcast model. It‟s not such a great leap up
technically in comparison to SD to HDTV. In addition, many displays that support 120Hz can work with
active glasses and give a “Full 3D Ready” display at the same cost as a 2DTV. The only extra cost is
active glasses. The passive polarised displays do permit a greater flexibility of glass design and are
suited to when you might need to support many viewers at the same time. To apply the polarization
plane to the LCD does require additional cost but at mass volumes this is not considerable. To
compromise 3DTV by limiting consideration to options that only go inside a video frame limits quality,
evolution potential, user experience, the option of 2D/3D single EPG channel and denies the highest
quality 3DTV to the consumer.
Finally a point to consider - if we are to have a new generation of “Full 3D Ready” set top boxes should
this be used as a way of future proofing to cope with 1080P50? If not at this rare junction in time how can
1080P broadcasting ever occur?
Future technologies
3.3 High Frame Rate (HFR) Television
Richard Salmon, Sam Davies, Mike Amstrong, Steve Jolly, BBC R&D, UK
Over 70 years ago, the TV frame/field rates were chosen, to: exceed the threshold for apparent motion,
avoid visible flicker (on small screens on these days), avoid interaction with the mains frequency and
provide a way of showing cinema film on TV systems. The current 50/60Hz TV was a match to standard
definition pictures and smaller CRT displays. But it is not a good match for larger displays, increased
picture resolution and sample-and-hold display technology (such as LCD).
Because the camera has a shutter that is open for 1/50 th of the second, you get a loss of detail on
moving objects. So, the static objects in the background are nice and sharp, the moving object is blurred
out by the camera integration [6]. If you have a long shutter, then you have motion blur. If you have a
short shutter you loose of the smoothness of the motion and introduce temporal aliasing (leading to jerky
motion and spoked wheels running backwards). The short shutter will sharpen the picture, but you
reduce the amount of light coming in, hence causing a loss of sensitivity.
Consider a ball moving across the screen [8]. We want the ball to remain looking like a ball as it moves.
If you capture it with a short shutter, you get nice sharp images (but juddery motion) – with a 50% shutter,
the images are still somewhat blurred out – but with a 50% shutter at double rate you get much sharper
images and much smoother motion as well, without using excessive camera shuttering.
Another way of looking at the problem is, say for example you are following the action in a football match
and you have upgraded your cameras and broadcast system from SD to HD, the action still happens at
the same speed. If you follow this action by panning at the same speed as in SD, since you have got 3
times more horizontal pixels it is 3 times more blurred as it was in SD [11]. You lost all the advantages of
HD. So if you increase the resolution still further, you have to slow down the rate of panning. The
problem is that the dynamic resolution of HDTV is actually no better than the dynamic resolution of
SDTV [11].
Historically, about 20 years ago, the BBC proposed that we should have a 80fps for HDTV, in part
because we managed to get a CRT to work at 80 H
© EBU 2009 / Production Technology seminar / January 27 - 29, 2009
Reproduction prohibited without written permission of EBU TECHNICAL & EBU TRAINING