Quote:
Originally Posted by carmenchu
Media type = image/webp, as per https://en.wikipedia.org/wiki/WebP
As webp offers almost double quality for half the weight than jpg, I am thinking to change the covers of my personal books to that format, besides using them inside.
Inside is not a problem for me, nothwistanding the wrong media type (I read in calibre viewer, and have checked already).
Cover, however, got messed when inserting it in sigil (by hand)... |
For me since I use eInk readers for most of my reading, webp is not an option. As you have already noted, the QT Webengine code used in calibre will not handle WebP consistently including my covers where the SVG wrapper use to simplify my life may be causing issues.
For work, we tried WebP on a couple of webservers and it was a total PITA. We still needed to keep the JPEG, PNG, etc. images for web browsers which did not support WebP and the ~25% compression increase still left us chewing up server hard drives like we got them for free. Even now 5 years later, we run about 15% of browsers that do not support WebP. And the supported browsers are a of a weird mix to support since we have to detect browsers that support lossy WebP, browsers that support lossless and lossy WebP with alpha support and browsers that support WebP animation.
I do wonder about the claim of double quality for 50% of the file size. In our testing, we found ~25% better compression for WebP lossy compared to JPEG. This was going for the same visual quality from DSLR produced raw format images. When we tried maximum quality, the difference between WebP and JPEG was pretty close to 3% which is negligible when we had to support both formats. The test done by Google using random images skimmed from the web showed about the same 25% reduction in file size compared to those produced by Re-JPEG when negative compression gains were allowed with an attempt to maintain a PSNR of ~42.