Comment by huhtenberg | Hacker News Reader

Comment by huhtenberg | Hacker News Reader

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For the lazy - http://jpegmini.com

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I grabbed 4th pair of their demo image [0], the high quality image is about 4.8M, the JpegMini'd version - 1.3M.

Then I took the high quality image and started bumping up standard JPEG compression level until I reduced the file size to 1.3M. That mapped to 17/100 setting, with 1 being highest quality, 100 - highest compression).

Then I made an arithmetic per-pixel diff between the original high quality image and two 1.3M versions. Cropped them to 2000 x 2000 and saved as PNGs (cropping is to fit the imgur file size limits). Here they are -

http://imgur.com/1FOwXhq

http://imgur.com/3efRooj

Now, have a look and tell me that JPEGMini hasn't got something exciting going on.

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[0] http://media.jpegmini.com/homepageImages/20121203/hipnshoot....

Haha, I only kind of skimmed your post then downloaded that file. I opened the images and was like "I don't know how high-quality this is. The images look exactly the same to me." And then I saw the file sizes and had the ah-ha moment.

Maybe I'm not the most knowledgeable guy here, but I really don't see what you're getting at. The per-pixel diffs look nearly the same. I downloaded the "hipnshoot.zip" and yes the photos look identical. But then I fired up gimp and re-compressed the high quality photo to reduce the size even more than the "jpegmini" version, and I can't tell the difference. Here are the file sizes:

-rw-r--r-- 1 tim users 4930482 Dec 1 21:22 hipnshoot.jpg

-rw-r--r-- 1 tim users 1310430 Feb 26 08:27 hipnshoot_gimp.jpg

-rw-r--r-- 1 tim users 1352882 Dec 3 09:16 hipnshoot_mini.jpg

I put them here: http://www.rareventure.com/jpegmini/

"hipnshoot_mini.jpg" is the "jpegmini" version and "hipnshoot_gimp.jpg" is the one I compressed with plain old gimp.

I don't see much of a difference. Is that the point? Are you saying that JPEGMini are just compressing to ~83% quality?

No, there is a noticeable difference.

JPEGMini diff shows less color fringing (fewer "colored" pixels) and it also appears to better preserve edges and outlines.

I'm not sure how much it could change anything here, but Imgur also compresses images when uploaded. Maybe try min.us?

PNG is lossless.

JPEGmini better preserves color information, but it doesn't seem to be that much better.

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