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Grumpy.


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comment Utilities for comparing different JPEG compression engines?
@PhilipKendall - Good point, moved.
2d
revised Utilities for comparing different JPEG compression engines?
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revised Utilities for comparing different JPEG compression engines?
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Dec
17
accepted Utilities for comparing different JPEG compression engines?
Dec
17
answered Utilities for comparing different JPEG compression engines?
Dec
17
comment Utilities for comparing different JPEG compression engines?
Anyways, apparently ImageMagick uses libjpeg, which is also used by PIL, so I've basically already got that covered anyways.
Dec
17
comment Utilities for comparing different JPEG compression engines?
Also, again, I don't need information on the analysis part (I understand that fairly well). I'm /only/ looking for information regarding what varies between different JPEG libraries.
Dec
17
comment Utilities for comparing different JPEG compression engines?
I was interested in exclusively the differences between different JPEG systems. As I said, my end goal is to be able to automate the determination of whether one image is a recompressed version of another. My image corpus is probably 90% JPEG, 10% PNG, and basically nothing else. No one really uses webp images or anything like that.
Dec
17
revised Utilities for comparing different JPEG compression engines?
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Dec
15
comment Utilities for comparing different JPEG compression engines?
@MarcinWolny - I asked on StackOverflow and got closed. So not, it apparently does not. Anyways, I know how to do the analysis, that parts easy. It's getting an idea of what's out there that is hard.
Dec
11
comment Utilities for comparing different JPEG compression engines?
I would argue that understanding image compression is a core part of modern photography. If there is a stack exchange better suited to the question, I'm open to moving the question.
Dec
11
awarded  Yearling
Dec
11
comment Utilities for comparing different JPEG compression engines?
Basically, I need a decent corpus of images compressed with different tunable parameters to do any sort of analysis.
Dec
11
comment Utilities for comparing different JPEG compression engines?
You're missing the point, there are a lot of tuneable options in the JPG specification and they vary between different implementations. Some applications expose some of them (GIMP), some have hard-coded values (Photoshop). Claiming the only thing that can vary is the compression degree is flat-out wrong.
Dec
11
comment Utilities for comparing different JPEG compression engines?
Basically, I'm seeking to be able to determine, with decent accuracy (99%+), if/which image out of two is closer to the original, in an automated manner.
Dec
11
comment Utilities for comparing different JPEG compression engines?
2. I'm doing statistical analyses. I'm not using photoshop, I'm using a script I wrote that directly quantifies the entropy-per-pixel. Just "looking" at something has basically zero scientific rigor.
Dec
11
comment Utilities for comparing different JPEG compression engines?
Sigh. 1. There are very, VERY much different (Look at the section labeled "Rainbowing") approaches and different choices with regard to constants and such in the design of the compression system. The JPEG standard may be well-defined, but there are LOTS of tuneable parameters for the actual compression that are all well within the standard, and vary from software to software.
Dec
10
comment Utilities for comparing different JPEG compression engines?
@PhilipKendall - Good point. I could have sworn it had a lossy option, Whoops?
Dec
10
revised Utilities for comparing different JPEG compression engines?
edited title
Dec
10
asked Utilities for comparing different JPEG compression engines?