[mythtv-users] OT: 4K TV. But why (yet)?
Michael T. Dean
mtdean at thirdcontact.com
Thu Dec 3 13:40:24 UTC 2015
On 12/03/2015 08:05 AM, Brian J. Murrell wrote:
> On Thu, 2015-12-03 at 11:35 +0000, Duncan Brown wrote:
>> On the Mythtv side of things I don't have any actual 4k content to
>> watch
> Indeed. I notice that in the stores all of the 4K TVs are showing
> slideshows of hi-res (still) photography, of course to show off their
> image detail (and it is stunning!), but I suspected that the still
> photo slideshows are in absence of being able to show any real video
> content @4K.
>
> So what are people buying these things to watch?
FWIW, there's more information in a 1920x1080 pixel image than can be
displayed with a 1920x1080 pixel display--it actually takes an output
display of almost 2x the sample width and 2x the sample height to render
all the information provided by an image. So to display all of the
information about a scene that's contained in a 1920x1080 image, you
would require a display of nearly 4k.
That said, the challenge is doing the appropriate math to extract said
information from the samples provided, and for video, an additional
challenge is doing it fast enough. I don't think any hardware or
software is able to fully extract that information from video images and
display it real time, but they all have tricks which tend to extract
some of the information for display. This is why when you watch a
1920x1080 video on a 3840x2160 display, you don't see 4-pixel blocks of
the exact same color. However, unfortunately, some of the vendors use
some cheats or just plain bad algorithms in scaling that may make the
display look far less "real" (less like the original scene) than a 1:1
pixel-mapped output (at least one vendor uses an algorithm that, IMHO,
tends to make everything look like CGI). But, if you've configured your
MythTV system to output at 4k resolution, you won't get any scaling from
the display device, so you can avoid their scaling algorithms--though
they may have other image processing algorithms that may still be used
(and the device may or may not allow disabling those algorithms).
Mike
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