This will be popular with web designers who will be very keen to have a lossy image format that supports an alpha channel for variable transparency.
I would like to see some hard figures for perceived image quality versus file size. Google says this:
<<we randomly picked about 1,000,000 images from the web (mostly JPEGs and some PNGs and GIFs) and re-encoded them to WebP without perceptibly compromising visual quality. This resulted in an average 39% reduction in file size>>
...but that doesn't mean much. I could probably take a million existing JPEGs and re-compress them more aggressively (but still as JPEGs) without "perceptibly compromising" visual quality. At least, if visual quality is not rigorously measured but is just "handwaving". |
Here is Google's comparison gallery:
http://code.google.com/speed/webp/gallery.html
Some of the images look perceptibly different to me, even in the scaled-down form. For example, the NFL player's skin looks lighter in the WEBP version. But as Google appears to have started with pre-compressed JPEGs, the gallery comparisons are bogus anyway.
Although these images are licensed under Creative Commons Attribution, and Google provides a link back to some image search results at Wikipedia, Google doesn't have the courtesy to acknowledge the names of the creators of the pictures they used. That's just pathetic. |
