webp image bad quality?

[zed140]

Just a question, it's me or the webp format also destroy image quality?

[Pickysaurus]

Webp can be "lossy" or "lossless" depending on if file size or quality is prioritised. It also varies depending on the quality of the original image. Because we're serving images for the web, small file size is slightly higher priority than quality. Otherwise the pages on the site will take a very long time to load.

[zed140]

In this case if I want post an image, it's preferable I post the original png instead of a already compressed jpg to reduce the final quality loss. Thank.

[lancegeis]

quite a bump on this subject, the webp compression borks the black level, artifacting pictures, but there is no real solution for this, others algos wont do better.

 

an example with a difficult picture to compress, the black is at the very limit, even downsizing gives crushed blacks. It's original size is fine however, so watch it in fullscreen by clicking the link

https://i.ibb.co/wLrh3ZG/2k-Skyrim-SE-2023-07-21-16-12-21-upscayl-4x-remacri.png -png

 

 

https://staticdelivery.nexusmods.com/images/1704/1798547-1717309647.png  - Webp

 

some artifacts.

 

 

Jpg max compression 4:2:0 84% quality has better shadow details, for the same size ! because it compresses the shadows progressively, reducing the perceivable black aureolas. Technically degrading the picture more, perceptually it is more correct. (but the rest of the picture is degraded much more than webp)

https://i.ibb.co/CtHFrfZ/2k-Skyrim-SE-2023-07-21-16-12-21-upscayl-4x-remacri.jpg -jpg 4:2:0 84% quality same size than webp, 290kb

 

Avif is slightly better but it has a server cost to compress for acceptable result, it's clearly less efficient.

JPEG XR preserves the black better without very annoying (still there, less perceivable) artifacts but at slightly higher size, 380 kb, at a specific compression ratio, too much and it breaks black, too high and it artifacts even more. Also, it cannot be read by some browsers.

 

After testing, webp is a logical choice for compression.

HOWEVER, we could have an option for a webp lossless hosting and browsing (nexus would always provide lossless pics when available, if someone hosted a lossless pic), at a price on top of the actual premium service. Like lossless audio on streaming platforms. If i remember correctly, many years ago, (2015-2017?) the pictures werent compressed that much and looked better. But it's maybe my memory.

I know, there is many 3rd party websites to host lossless pics, but it's a pain in the ass, to say the least. It would be comfortable to handle lossless pics on nexus and it could be another way to support this amazing modding platform.

2kSkyrimSE 2023-07-21 16-12-21_upscayl_4x_remacri.jxr

[SirCadsimar]

WebP is pain.

[NevverSWL]

The webp compression is either awful or Nexus is setting the amount with a very heavy hand. I upload my images as jpgs but, recently, have noticed a lot of artifacting in my uploaded images that were automatically converted to webp.  As an example, a jpg I uploaded at 783 kb got smashed down to an 101 kb webp file for a 1920x1080 image; that's excessive. Is this something that came about since the recent web site changes? I didn't have problems with images until fairly recently and what is going on now kind of defeats the purpose of even bothering to upload screenshots in the first place since they end up looking like trash.

 

My original jpg:

 

Nexus webp:

[JimboUK]

Look at this, the artifacts are painfully obvious, to be expected when a 1440p image is reduced from 1.6MB to 103KB, whatever setting is being used it's way too aggressive.  

https://www.nexusmods.com/newvegas/images/137127

It's so overdone that the image looks like the file was corrupt. 

If bandwidth savings need to be made wouldn't it be preferable to reduce the max upload size to 1MB and have people optimise their own images?

The original image for comparison.