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Update: Here's some very basic file comparisons. Special thanks to Erik Anderson of http://divineerror.deviantart.com http://divineerror.deviantart.com for the

by jjcm 16y ago

Update: Here's some very basic file comparisons. Special thanks to Erik Anderson of http://divineerror.deviantart.com http://divineerror.deviantart.com for the lossless images. In the folder is the original image, the compressed version of the image in both jpg and webp, and a enhanced difference map between the compressed version and the lossless image. http://jjcm.org:8081/webp http://jjcm.org:8081/webp Basic analysis shows that right now webp has better preservation of luminance, but at the expense of hue/color. I'll have a blog post up in a bit with a myriad of file tests, difference maps, percentage differences, and hue offsets in a bit.

astrange 16y ago
You shouldn't get any kind of percentage differences in the color channels, at any size above 8x8 blocks in the image. If the entire image is offset that most likely shows a bug in your conversion process.
Groxx 16y ago
Awesome set of pictures. I can live with the squares of WebP better than the hugely-visible gradients of JPEG, methinks. Subjectively, I'd say those images show it to be definitely superior, by a pretty large margin. Very impressive. I can easily live with the 2x decode / 8x encode with those results. edit: though, if there's no alpha capabilities, count me out. Yes, that's my deciding factor.
- jjcm 16y ago
  Don't jump on it yet, alpha capabilities aren't the only thing that it's missing. After some analysis it doesn't support color profiles - greyscale being the biggest factor here. About to upload a sample black and white image, and you'll see the issues there.
  - Groxx 16y ago
    I was wondering if profiles might have been the reason for some of the larger hue/sat differences (over the whole image). Will gladly keep looking, it's interesting either way :) Thanks!
- asmosoinio 16y ago
  "We plan to add support for a transparency layer, also known as alpha channel in a future update." http://blog.chromium.org/2010/09/webp-new-image-format-for-web.html http://blog.chromium.org/2010/09/webp-new-image-format-for-w...
jjcm 16y ago
Update 2: Here's the blog post along with mean delta values for both RGB and Luminance from the source image: http://news.ycombinator.com/item?id=1746621 http://news.ycombinator.com/item?id=1746621

by jjcm 16y ago

astrange 16y ago

You shouldn't get any kind of percentage differences in the color channels, at any size above 8x8 blocks in the image. If the entire image is offset that most likely shows a bug in your conversion process.

Groxx 16y ago

Awesome set of pictures. I can live with the squares of WebP better than the hugely-visible gradients of JPEG, methinks. Subjectively, I'd say those images show it to be definitely superior, by a pretty large margin. Very impressive. I can easily live with the 2x decode / 8x encode with those results. edit: though, if there's no alpha capabilities, count me out. Yes, that's my deciding factor.

jjcm 16y ago
Don't jump on it yet, alpha capabilities aren't the only thing that it's missing. After some analysis it doesn't support color profiles - greyscale being the biggest factor here. About to upload a sample black and white image, and you'll see the issues there.
- Groxx 16y ago
  I was wondering if profiles might have been the reason for some of the larger hue/sat differences (over the whole image). Will gladly keep looking, it's interesting either way :) Thanks!
asmosoinio 16y ago
"We plan to add support for a transparency layer, also known as alpha channel in a future update." http://blog.chromium.org/2010/09/webp-new-image-format-for-web.html http://blog.chromium.org/2010/09/webp-new-image-format-for-w...

jjcm 16y ago

Update 2: Here's the blog post along with mean delta values for both RGB and Luminance from the source image: http://news.ycombinator.com/item?id=1746621 http://news.ycombinator.com/item?id=1746621