I read somewhere its better watching 1080p content on native 1080p (Full HD) TVs, because they keep ORIGINAL video resolution without down\upconverting .
If that's true, so buying 4k TVs without any much 4k sources around (While many FHD and HD contents available) , mean wasting both money and quality, isn't that?
On CNET's article:
we've found that 1080p Blu-ray upconverted to the 4K screens looks great, although not appreciably better than 1080p on a 1080p TV.
Upsample by an integer ratio can be completely blameless, just repeating pixels and lines gets it done, no new information, and you get only the original resolution displayed, but no losses either.
This zero order hold based approach tends however not to be popular, and the amount of processing to do anything else rises rapidly especially if you either want to apply filtering over more then a very localised area or play dynamic games to try to give the impression of more resolution (Popular with consumer gear which compounds the messing about by not having sufficient processing to do it well).
Just doing a 2D sinc interpolation is pretty close to blameless (potentially 90% bandwidth or so if you can afford to throw sufficient processing at it), and takes the edges off the pixel doubling.
However for most reasonably sized tellies at reasonable viewing distances, HD is in fact just fine, 4k is nice on a computer monitor where you are sat 18 inches away from a 30 inch screen, but that is not the usual use case for telly. You may find a search on the term "Circles of confusion" to be informative.
Now HDR (On a set that has the brightness and contrast ratio to pull it off, not technically easy) is a real win even on a SD screen.
Any resulution changes cause a loss of quality. For the case of upscaling you need to calculate data for the pixels and allthough there are devices with hardware and software that has powerful tools to do so, they will never be able to keep sharpness and detailed textures and fast movements in the original quality. Always remember that you need four pixels to reproduce one if you double resolutions to height and width.
Matched resolutions will typically yield best percieved visual results.
If youve ever watched an “actual” 525/480 SD signal on an HD set you know exactly what I mean.
Did TV really used to look that bad? No. A 50” Standard Def Tube TV will produce a FAR better image of Standard Def material than a Sony Bravia 50” 1080 Set with the same feed.
