On Saturday, October 19, 2013 12:30:15 PM UTC+1, Jeff Muizelaar wrote: > ----- Original Message ----- > > > On Saturday, October 19, 2013 12:12:14 AM UTC+1, Ralph Giles wrote: > > > > On 2013-10-18 1:57 AM, Yoav Weiss wrote: > > > > Do you have such a sample? > > > > > > For what it's worth here's an image I made quite awhile ago showing the > > > results of my own blind subjective comparison between codecs: > > > http://www.filedropper.com/lossy > > > > I agree that in this comparison JPEG is clearly the worst. However, the > bitrate that you are using here is well below the target for which JPEG is > designed to be used and the quality of all of the image formats is lower than > would be acceptable for nearly all purposes. This makes these results much > less interesting than at quality levels typically used on the web. > > > > -Jeff
I completely agree. This is why I'm don't want this image to be considered as good proof of which codec is superior. I had another image exactly like this where I had comparisons around 35kb which was a much more realistic quality level for all the codecs but the differences in visual quality loss was still noticeable, but I seem to have lost it. My own subjective findings were that quality of each codec was roughly the same order, with JPEG always being identifiable the worst until file size raised to the point were it was impossible to easiy tell the difference between any of the lossy compressed images. I think if this test image were compressed on a typical web page it would typically be a 80kb JPEG or so, and at this level of quality it's difficult for a human to differentiate between a webp or jpeg-xr image of the same size or even the original lossless image for that matter in some cases. In this respect subjective blind testing by humans fails, but my point is I never observed anything like JPEG performing worse than JPEG-XR or Web-P and I'm very surprised to see that some algorithms are reporting that JPEG out performs WebP and Jpeg-XR by a wide margin at some quality settings, in stark contrast to what other algorithms report (RGB-SSIM) and what my own and what I believe other subjective blind tests would report. _______________________________________________ dev-platform mailing list dev-platform@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-platform
