Jyrki Alakuijala

In WebP lossless I use a 'double RLE' mode. The double RLE mode can repeat the previous pixel, or copy N pixels of the previous row at respective locations. I...

I'd be happy to contribute as an co-author of this chapter, or possibly only in the content planning part and helping to scope this chapter. I have experience in image...

I'd be happy to help contribute as an author to this chapter.

There is generation loss in guetzli images. One should run guetzli only once. The same applies to most lossy compression. https://en.wikipedia.org/wiki/Generation_loss

Butteraugli has been optimized for the human vision at a viewing distance of 1000 pixels. When the viewing distance is more, some other approximations can be better. Also, it can...

Would "Inferior compression density" be a better word for the title than "Strange behavior" ?

Without seeing the images, I suspect that these images have a certain level of noise that is present in the higher resolution images, but not in the lower resolution subsampled...

Can you repeat this bug with guetzli? If yes, please send us the image that causes this to happen.

@mdelarioja Which version of Guetzli are you using? Which quality levels do you observe the problem? Could you share the image, too? While there is no full solution to this...

I will be trying a new candidate fix for this problem -- to make butteraugli asymmetric in relation to high frequency artefacts, i.e., to punish smoothing less than adding new...