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uk.tech.digital-tv (Digital TV - General) (uk.tech.digital-tv) Discussion of all matters technical in origin related to the reception of digital television transmissions, be they via satellite, terrestrial or cable. Advertising is forbidden, with no exceptions.

New technologies?



 
 
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  #31  
Old February 12th 18, 12:57 PM posted to uk.tech.digital-tv
tim...[_2_]
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Default New technologies?



"R. Mark Clayton" wrote in message
...
On Monday, 12 February 2018 09:34:41 UTC, tim... wrote:
"R. Mark Clayton" wrote in message
...
I am fortunate to have above average acuity, but if you can't easily
tell
SD from HD at 3.5m from a 42" screen, then I would seriously suggest an
eye test.


Wearing my current prescription lenses

There was a minor difference in that it was easier to read the title of a
book on the shelf behind the person being interviewed.

But in the moving part of the picture there was no discernable difference

IMHO

there was in the sound level though

tim


HD is better on satellite due to the higher bit rate.


I have Freesat

Full HD (1080i) is obvious at that sort of range - is your TV perhaps only
HD ready (720p)?


1920 * 1080

tim



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  #32  
Old February 12th 18, 07:12 PM posted to uk.tech.digital-tv
NY
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Default New technologies?

"Martin" wrote in message
...
On Sun, 11 Feb 2018 07:25:35 -0800 (PST), "R. Mark Clayton"
wrote:

I am fortunate to have above average acuity, but if you can't easily tell
SD from HD at 3.5m from a 42" screen, then I would seriously suggest an
eye test.


Depending on the quality of the upscaling?


Are you saying that an SD-resolution picture shown as an SD broadcast will
be less sharp than the same SD picture upscaled to an HD broadcast? I
realise that this is an unusual situation: normally SD broadcasts are
downscaled from an HD master, as opposed to HD broadcasts being upscaled
from SD master. I suppose there may be fewer compression artefacts on the HD
version than the SD because of the more efficient encoding gives less
compression for similar bitrates.

I can see this by looking closely (eg at a couple of feet away) at an SD and
HD version of the same programme: the HD has extra detail, sure, but it also
has fewer compression artefacts.

  #33  
Old February 12th 18, 09:35 PM posted to uk.tech.digital-tv
Jeff Layman[_2_]
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Default New technologies?

On 11/02/18 15:25, R. Mark Clayton wrote:
I am fortunate to have above average acuity, but if you can't easily tell SD from HD at 3.5m from a 42" screen, then I would seriously suggest an eye test.


I had one last July, and can read further down a Snellen chart than
average eyes can.

For those interested, there is a lot to consider at
https://carltonbale.com/does-4k-resolution-matter/ (in relation to 4K,
but the same reasoning applies to HD). After reading the webpage, and
especially the comments, I am no wiser, other than realising that the
number of pixels and visual acuity aren't the only factors at work here.

--

Jeff
  #34  
Old February 13th 18, 10:30 AM posted to uk.tech.digital-tv
Max Demian
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Default New technologies?

On 12/02/2018 23:04, Martin wrote:
On Mon, 12 Feb 2018 20:12:00 -0000, "NY" wrote:

"Martin" wrote in message
...
On Sun, 11 Feb 2018 07:25:35 -0800 (PST), "R. Mark Clayton"
wrote:

I am fortunate to have above average acuity, but if you can't easily tell
SD from HD at 3.5m from a 42" screen, then I would seriously suggest an
eye test.

Depending on the quality of the upscaling?


Are you saying that an SD-resolution picture shown as an SD broadcast will
be less sharp than the same SD picture upscaled to an HD broadcast? I
realise that this is an unusual situation: normally SD broadcasts are
downscaled from an HD master, as opposed to HD broadcasts being upscaled
from SD master. I suppose there may be fewer compression artefacts on the HD
version than the SD because of the more efficient encoding gives less
compression for similar bitrates.

I can see this by looking closely (eg at a couple of feet away) at an SD and
HD version of the same programme: the HD has extra detail, sure, but it also
has fewer compression artefacts.


Sony upscales SD channels to make them look sharper
https://www.makeuseof.com/tag/upscal...s-it-worth-it/


All the upscaling (SD-1080p) I've seen works quite well. The only time
it looks wrong is if you freeze the picture in which case lines that
aren't horizontal or vertical look jagged. Also the picture looks rather
soft, though you need a good HD signal source to compare it against.

--
Max Demian
  #35  
Old February 13th 18, 11:46 AM posted to uk.tech.digital-tv
Terry Casey[_2_]
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Posts: 768
Default New technologies?

In article ,
says...


in 1990, I was demonstrating live HDtv at Wimbledon on a large screen
Trinitron. You could see the mesh in the net on the picture that was taken
from behind the server showing the whole court. People wouldn't believe it
was television.


In 1992 I saw a demonstration of the Scandinavian HD Divine
system at the IBC in Amsterdam.

https://tech.ebu.ch/docs/techreview/...appelquist.pdf

What caught my attention was a shot of a man doing a piece to
camera in the open air. A couple of short hairs were standing
up on the top of his head and were waving around in the
breeze.

Each individual hair was clearly visible!

--

Terry

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  #36  
Old February 13th 18, 06:10 PM posted to uk.tech.digital-tv
Bill Wright[_3_]
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Default New technologies?

On 13/02/2018 12:46, Terry Casey wrote:

What caught my attention was a shot of a man doing a piece to
camera in the open air. A couple of short hairs were standing
up on the top of his head and were waving around in the
breeze.

Each individual hair was clearly visible!


If the hairs were catching the light they would excite more pixels than
their width would suggest, due to optical limitations such as flare.

Bill
  #37  
Old February 15th 18, 04:13 PM posted to uk.tech.digital-tv
Richard Jones[_2_]
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Default New technologies?

On 10/02/2018 09:19, Jeff Layman wrote:
On 09/02/18 23:39, Michael Chare wrote:
On 09/02/2018 16:24, Brian Gaff wrote:
Is there really a call for this sort of definition outside of very large
screen public use?
** Brian

Yes, even on a 40" screen which was the smallest UHD TV I could buy
about a year ago, the picture does look better. I would like to see more
UHD channels on satellite.


The problem is that most people don't sit near enough to benefit from a
4K picture. I doubt that many sit close enough to really benefit from HD!


Completely agree. A couple of summers ago a few of those annoying
thunderfly bugs (thrips) got between the backlight and lcd layers of my
telly. Luckily at my seated position they are not visible but move to a
couple of meters away and they certainly are.
Now these bugs probably black out a line of three or four HD pixels yet
at the viewing distance not discernable. So I'm already well into eye
resolution limitation rather than pixel quantity limiting the quality.
I think that often what is perceived as better UHD picture quality (at
distance) is the increased bit rate rather than raw resolution. That's
something that could be fixed by broadcasters without any hardware
upgrades but I guess doesn't have the same saleability to the general
public.
  #40  
Old February 17th 18, 08:39 AM posted to uk.tech.digital-tv
Jim Lesurf[_2_]
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Posts: 4,326
Default New technologies?

In article , Roderick Stewart
wrote:

Possibly not quite what you were referring to, but I often see shots
where the books on the shelf in the background are easy to read because
they're the only bit of the scene actually in focus, the foreground
person being slightly soft.


If I had to guess a reason for this, I'd suggest too much reliance on
automatics and a lack of understanding of a) basic optics, and b) how
the equipment works.


We've been watching the "House through time" series. In a number of places
in this I've noticed that some parts of the image are in focus whilst
others are blurred.

At first I assumed it was simply that the camera had too narrow a depth of
field. But I then saw examples where the background was all at the same
distance, but parts near the presenter were in focus whilst other further
away were not. So I concluded this is another 'effects control' the
director had found and kept playing with. A new toy. Something to add to
wobblycam, Sun in vision with lots of glare, etc, etc.

Jim

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Electronics https://www.st-andrews.ac.uk/~www_pa...o/electron.htm
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