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frik

hq4x looks better (IMHO), sadly the website is offline (default blank wordpress site): http://hiend3d.com/hq4x.html

backup on archive.org: https://web.archive.org/web/20120630044334/http://www.hiend3...

http://en.wikipedia.org/wiki/Hqx

Source: https://code.google.com/p/hqx/source/browse/trunk/src/hq4x.c

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Only if you look at the first ones. All of Boo, Dolphin, all of SoM, Invaders, Golden Axe, Windows assets and Lost Vikings look great and have vastly reduced artifacts compared to hqx. Also, according to the paper abstract[0], it outputs vector, not scaled up bitmap.

[0]: http://research.microsoft.com/en-us/um/people/kopf/pixelart/

As you say: It depends. E.g. the sword looks better with hq4x, because the result isn't rounded.

The Super Mario and Secret of Mana stuff works quite good, except it changes the facial expression on "Peach 2". I'd like to see Donkey Kong Country 1/2/3, Megaman (NES and SNES) and Chrono Trigger processed by this. And not just the sprites cut out of the background but embedded in a scene.

"ours" Peach 1 suddenly looks really sad.

Look at Axe Battler 2 - if the sword isn't vertical, then the result is not superior. Unless, of course, you think the guy is wielding a sawtooth blade.

Not to mention that muscles have a smoothly-graded tone under the 'ours' algorithm, whereas hq4x has an unlifelike blocky effect.

Honestly I think hq4x and "Ours" both look like ass for both of the Axe Battlers. Nearest neighbor is a better choice for either of them. EPX on either is acceptable.

No, hq4x is still better on almost all of them. Microsoft's makes everything too round and blobby. It pretty much only works really well when everything is round, like in Boo. But look at what it does to the Golden Axe characters' faces.

hq4x keeps angles when it should not, degrading many features in the process, and that bothers me much more than the overall change to a bit more blobbiness. Look at the outline of Bowser's horns and mouth, Toad's cap outline, Fake Sage's moustache, or Axe Battler 2 sword. The mouths of invaders are also faithfully reproduced. In the Ports icon, the cable is correctly represented, and the port itself has volume instead of becoming two planes as in hq4x. On the Keyboard one, hq4x produces a good icon, although it rounds the keys a little, while "ours" produces a non-faithful in style but nonetheless correct result. Control Panel is interesting, as "ours" looks like the hq4x version has melted, but the hq4x version produces a result that is semantically similar (piano keys, weird mouse shape, angles in letter) leading me to think the original icon is not exactly the best pixel art material (maybe due to palette constraints).

Maybe the results of "ours" aren't exactly faithful in style in some cases, but they're globally consistent, and I find the shapes semantic more truthful. As for hq4x by itself, I actually prefer the original sprites overall.

I noted the same issue with round vs sharp sections. Honestly, what this needs is a blending function, kind of like how they do intense shocks in fluid dynamics, where it would use MS's algo in areas where it detected significant roundness, and then blend into the hq4x algo in areas where there's more angular sections, like in the treasure box.

I think we're trying to optimize different functions.

For Bowser, I think hq4x is fine (the mouth needs not have a smooth contour like a human's - compare with a dinosaur or a crocodile), but you are giving more weight to the fact that the shaded part on the bottom right of the mouth is broken in several pieces, instead of being a single piece like in ours.

For Fake Sage, I think hq4x does better. A pointy moustache is fine. The "ours" version is practically melted, and hardly recognizable as an old man - it looks more like some sort of fish shaman.

For Axe Battler 2, the shaded part of the sword is jagged in hq4x, but that doesn't bother me. Same thing for the broken black outline in the leg. I am much more bothered by how "ours" messes up his face.

In general, I would say that "ours" is better at putting together some parts that are supposed to be a single line, while hq4x separates them (especially with thin shadows). But graphically, hq4x's result is much more faithful to what the sprite is supposed to represent. With "ours", everything looks like melted ink, or like it's been seen through a wet pane of glass in the rain.

It would be nice to see if it's possible to combine "ours"'s better detection of continuous shades with hq4x's better preservation of straight lines and details.

I think the lesson here is that it is subjective and the ability to use multiple such tools together would be best.

I agreed with you, but then I realized they're representing hqx deceptively.

There was a video posted here, with them rendered at the same resolution side by side.

https://news.ycombinator.com/item?id=7307975

It's really a matter of taste in this video.

> they're representing hqx deceptively.

A big difference in the techniques is that hq4x is a fix-rate upscaling, whereas Microsoft's can handle arbitrary target resolutions. At the same rez, they are pretty equivalent. But, MS has the option to go higher. HQ8x has not yet been developed. I doubt that HQ(arbitrary)x is possible without completely changing the algorithm.

Not just higher, but non integer/power of two.

I agree, that's huge advantage. That's why I said it was a deceptive representation, but not an invalid one.

I took great care to compare 4x, only considering 16x as a zoom, especially since "zoomed in", it blows out the details too much so you lose the global picture. Still, 16x means HiDPI will make it looks crisp as hell for the same physical size.

As for the video, the dent in Mario's cap outline and the similar angles in the background outlines ruins hq4x for me, while I could live with the "200"/"400" lettering (which looks better on hq4x) because it disappears quickly (but does not bode well for other cases where text appears)

even so. I suspect a live rendering of the vector process would be fairly attractive. I'd love to see this technique used on the textures for n64 games. The rendering times wouldn't be such an issue in that case.

hq4x definitely looks the best and most accurate. If it only further smoothed the jaggies, it would look phenomenal.

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