Guspaz wrote:
I don't think a computer outputting 1080p scaled to 4K can really be compared to 240p scaled to 1080p scaled to 4K. The whole reason that it still looks so good for the 240p content is because the 1080p signal you feed the TV has very large blocks of identical pixels, while a true 1080p computer image would have distinct pixels.
This is true. All you really need for 240p content is that good *First* step of integer scaling of 2 to 3 x before upscaling normally as you need those source pixels preserved large enough that upscaling can't deform them significantly. (For pixel games. 3D rendering is different ball game).
When it comes to true 1080p content upscaling to 4k, integer scaling still matters but it's context dependent on whether a game is 3D rendered or 2D.
And if 3D, how well that 3D is rendered in terms of undersampling issues. (Aliasing).
Games with a lot of undersampling when integer scaled to 4k, will produce a result similar to scaling low res pixel art to higher resolution without integer scaling. It's trying to interpolate values between the undersampling that it physically cannot and in the process will just make it blurrier without solving the problem to begin with. (The undersampling remains. It's just blurrier now) Therefore the best option is to preserve the undersampling as is and it will retain the sharpness and visual make up of what you'd see on a native monitor.
Now 3D content that isn't heavily undersampled and closer to the ground truth (Somewhat like upscaling video content) will fare much better when upscaled and will look good whether you integer scale it or not and it becomes a matter of preference. You can have false positives with this and modern 3D rendered games because of the heavy use of Temoral Anti Aliasing. Consoles are too light to really render games with high quality Anti-aliasing. (Though the PS5/XBSX are powerful enough that you could render every game from the last 2 generations with extremely high quality Anti Aliasing at 1080p and even 4k, 60FPS or 30 depending on user preference. Because you can already do the same with weaker existing PC hardware. But you'll never see it on consoles) TAA is a very lightweight technique costing a fraction of a frame in render time. And due to this TAA depending on the implementation can cause an obscene number of artifacts that don't exist in a raw undersampled image. Or even reverse Anti-Alias the image and cause aliasing to exist that doesn't without the TAA as well. TAA is a whole can of worms that I could spend days talking about.
But let's get back to the point,
i've prepared some 4k videos illustrating both 240p content and various upscaling scenarios to 4k.
And 1080p 3D rendered content heavily undersampled (No AA) and with essentially no undersampling (very high quality AA) integer upscaled to 4k and upscaled with a simple bicubic resample.(As most TV scalers AFIK would not be well represented by a simple Bilinear upscale as it is very low quality).
I would highly encourage downloading these videos and playing them at 4k on a 4k native screen if you can. Google Drive's video player rencodes the video to 1080p.240p integer scaled directly to 4k https://drive.google.com/file/d/1rQydjD ... sp=sharing240p integer scaled 3x3 to 960x720 and then upscaled via Bicubic to 2880x2160 https://drive.google.com/file/d/1H9dF4A ... sp=sharing240p integer scaled 4x4 to 1280x960, bicubic upscaled to 1440x1080 and then that is integer scaled to 2880x2160 (Because why not? As you'll see the final results don't look much different)
https://drive.google.com/file/d/1qyB0Do ... sp=sharing240p upscaled directly to 4k via bicubic. https://drive.google.com/file/d/1SyUBOB ... sp=sharingThese were upscaled from a direct 1x scale 240p video capture from Duckstation (dithering disabled)and then encoded with an AviSynth script with MEGui to do the scaling in an offline render to show what scaling to 4k could look like. (Compression is middle of the road so does technically have some visible chroma loss on reds and some compression artifacts if you know what to look for)
1080p Content (A game with simpler 3D rendering is used, but more modern games will have more rampant undersampling problems. They are visible enough here to illustrate the point)
1080p no AA bicubic upscaled to 4k https://drive.google.com/file/d/1rq_uAP ... sp=sharing1080p no AA integer scaled to 4k https://drive.google.com/file/d/1mFPgPL ... sp=sharing1080p with AA integer scaled to 4k https://drive.google.com/file/d/1LVv10x ... sp=sharing1080p bicubic upscaled to 4k https://drive.google.com/file/d/12N3uPk ... sp=sharingdarcagn wrote:
What I'm most interested in seeing from 4K-native video processing devices is improved filters that more closely resemble real CRTs (like crt royale).
That stuff is definitely noticeably better on 4K output.
This would be the main benefit of a direct 4k scaler, but that would involve a frame buffer of some kind i'd imagine. But high res oversampling of CRT filters improves at lower resolutions as well.
Running those same shaders at a higher resolution and downsampling to 1080p has a noticeable improvement over direct 1080p rendering.
https://www.screenshotcomparison.com/comparison/10075More individual details up close will of course still look better at 4k native. But I don't imagine most people will be sitting 3 feet away from the screen, at normal viewing distance your eyes won't be able to discern details of individual pixels anyway. There is an ideal PPI to viewing distance ratio for every monitor based on resolution,size/PPI and distance where this happens. (And why a 1080p display with a good signal can still look just as fantastic as a 4k screen when viewed at the exact right distance.)