WebP Image Quality Issues

[lilebonymace]

before

after

you can clearly see even without zooming how all details are blurred, especially the background. the damage depends on the image, but generally all details are blurred, i can see that on most images

[LenaWolfBravil]

Thank you all for the image comparison! Yes, I see it now. It is more noticeable when contrast is higher. In particular, in the Skyrim image above it is quite noticeable even without zooming.

[wSkeever]

Before

After

[NevverSWL]

3 hours ago, Iluviel said:

Thanks for the feedback.

We'll discuss the image quality concerns internally and I will post a response by the end of our working week.

Very cool. Thank you!  

[NevverSWL]

3 hours ago, Pickysaurus said:

Out of interest, do you guys have high-resolution monitors? I can barely see the different on my 2560x1600 displays. (I'm not saying there isn't a difference, but I do have to look for it!)

No, there's nothing special about the resolution of my monitor, it's  24" 1920x1080 and I have it plugged into my laptop. It's also what I use to play the game and take the screenshots I posted. I can definitely see the differences between the images the others have posted.

[JimboUK]

2 hours ago, Pickysaurus said:

As I said, I can see a difference, but in Skeever's examples, it's exaggerated because it's super zoomed on a specific section of the image. Viewing the image at its normal size on the website is when I struggle to see the difference. 

These aren't zoomed in although they are a bit dark, the before image will have been compressed twice (once in Photoshop after editing and again after cropping for this) plus whatever Imgur has done to it, but you can still clearly see the wood panels, corrugated metal etc, the after is cropped from the Nexus upload, it's a blocky mess. I understand that you have to keep bandwidth under control and maybe one way would be to stop people uploading PNGs, there's little if any visual difference between a PNG and a quality JPG, but there can be a large size difference. 

 

Before... 

After...

[NevverSWL]

3 hours ago, Pickysaurus said:

Out of interest, do you guys have high-resolution monitors? I can barely see the difference on my 2560x1600 displays. (I'm not saying there isn't a difference, but I do have to look for it!)

Here's one I just uploaded where you can more easily see what's going on. Note the loss of detail, most noticeable in the hair, and artifacts in the red area and elbow.

Nexus webp:

Original on Imgur:

[BellCube]

@JimboUK To be fair, I've never seen a compression algorithm that handled dark stuff well

At least in my opinion (someone who does filmmaking stuff IRL from time to time and can spot when a room is slightly pink or green passively), I think the quality jump is noticeable—even in full-size comparisons displayed in the forum posts (smaller than they would be on the site itself). Blurry background vs non-blurry background makes an unexpectedly-large difference in the "feel" of an image.

[MrMason]

Thanks for raising this, what has happened here is that whilst optimising another part of the website we found some configuration that wasn't what we expected - specifically that we had .webp quality on all images set to 90 when the .webp default is 75. This results in some very large images that do not give a good experience to the majority of users.

We have updated that configuration and did some light touch testing on images and mod images to see what the effect was and we were struggling to see much difference so we deployed the change.

Looking at the examples you've provided we can see that 75 is too aggressive when displaying the full images and we'll look at increasing this quality either back to the 90 that it was before or see what else we can do.

I think it's highly likely that we'll be keeping all thumbnails on 75 quality as it's considerably faster for users to load the images.

I'll report back here in a few days when we've made the change ( the configuration & testing isn't as simple as it sounds! ).

[JimboUK]

31 minutes ago, BellCube said:

@JimboUK To be fair, I've never seen a compression algorithm that handled dark stuff well

At least in my opinion (someone who does filmmaking stuff IRL from time to time and can spot when a room is slightly pink or green passively), I think the quality jump is noticeable—even in full-size comparisons displayed in the forum posts (smaller than they would be on the site itself). Blurry background vs non-blurry background makes an unexpectedly-large difference in the "feel" of an image.

Absolutely and it makes sense that compression would target parts of the image that are less visible, but that stood out like a sore thumb. It's going to be fun when 8K gaming becomes a thing, I took some shots of New Vegas at that resolution and ended up with comically huge bitmaps that were still over 40mb when converted to JPG.