[opendtv] Re: TV Technology: A New Day Dawning... HDR Delivery
- From: Jeroen Stessen <jeroen.stessen@xxxxxxxxxxx>
- To: opendtv@xxxxxxxxxxxxx
- Date: Sat, 11 Jun 2016 08:06:47 +0200
Howdy,
On 2016-06-11 02:46, Manfredi, Albert E wrote:
Donald Cooleman wrote:
Word from the Technicolor CES analyst briefing was that it works and works well.
In spite of warnings that this doesn't work well.
I am not personally familiar with this particular project from
Technicolor. It is a big company with many projects.
There is a number of operations that you can do safely, like increase
the gamma a little, boost the bright scenes a little, boost the
saturation, etc. This can give attractive results, as long as you don't
expect to get the original HDR back. Let's not forget that there is
always a big market for up-conversion technology in new receivers, as it
helps solve the chicken-and-egg problem. We have seen the same with HDTV
("Digital Reality Creation", "PixelPlus"), widescreen ("SuperWide
mode"), 3D (2D to 3D), auto-stereo (2D or 3D to multi-view), wide color
gamut (gamut expansion), stereo audio (mono to pseudo-stereo),
multi-channel audio (stereo to multi), and now with HDR. Philips TV has
had a "superbright mode" for a number of years, enabled by LCD with 2D
backlight boosting. These things are inevitable.
On the practical aspects of HDR, I doubt that people will go to great lengths
to darken their TV viewing venues. So this, added to the fact that people
really like bright screens (Mark Schubin reports), will probably mean that HDR
displays will be *really* bright, in the bright parts of the image.
Up to 4000 nit, potentially. Not on large areas, because then many or
all HDR displays will go into power limiting. Ultimately it is up to the
director and the colorist to decide how high they want to go. We also
see HDR content that does not reach the stated peak brightness, because
that would not be an improvement. A night scene is still a night scene,
with an occasional highlight.
The other thing I wonder is just how much dynamic range compression is done in
TV transmissions, as a matter of course. In audio, it's completely commonplace,
and always has been. So I wonder if HDR to SDR conversion will be markedly
better, for SDR displays, than what we're used to seeing now from TV
programming already now.
Hard to say. The requirement of our conversion being invertible does
impose some constraints that "normal" SDR does not have. There is also
the limited number of tone mapping parameters versus a 1000-button
grading console. Then again, occasionally we've got compliments that our
SDR looked better than manually graded SDR. Maybe it does not matter if
you have fewer buttons, as long as they are the right buttons. We cannot
ignore the wishes of the colorist, what he wants has to be largely
possible, and he has to feel comfortable with our tools.
Some of the demoes look quite good, but is this exaggerated?
Clarke's law: "any sufficiently advanced technology is indistinguishable
from a rigged demo".
What I mean is that of course demo's are selected to look good. You
don't release a solution until you have confidence in it.
I mean, attempts to demo HDR on your typical and ubiquitous SDR displays has to
show SOMETHING cool, right? I'm guessing a lot of these demoes have to
exaggerate the amount of clipping and fading to black of the SDR image.
Otherwise, how would you get any amount of wow looking at the SDR demo?
That is something that cannot apply to us, because our SDR must always
be able to convert back into HDR. Hard clipping is not an option. We can
attenuate but not lose information on the SDR channel. Every tone
mapping function must be carefully chosen. The set is limited but the
process is rather intuitive. Our regular grader likes the job. Maybe
this is why it looks so good ?
Then again, in the HDR version you can achieve an amount of sparkle and
colorfulness that an SDR display simply cannot reach. The perception of
sharpness and depth and immersion is greater. Even without a direct
comparison with an SDR version you will know that you have always been
missing something. HDR is not hard to sell to the viewer. I suppose the
hard part is not to disrupt the delivery chain.
I haven't had such an interesting job in years, I feel good about HDR.
Best,
-- Jeroen
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