[mythtv-users] OT: 4K TV. But why (yet)?

[Michael T. Dean]

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