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identify -verbose to get jpeg quality

Posted: 2019-04-02T04:59:32-07:00
by figgis

I've noticed that imagemagick can't estimate the jpeg quality from a camera that I have.
Quality 0-30 works fine, but as soon as I go above 30, I get nothing from imagemagick

Code: Select all

$ identify -verbose image30.jpg | grep -i quality
  Quality: 53
$ identify -verbose image32.jpg | grep -i quality
It seems to be caused by this line: ... peg.c#L940

i doesn't reach 50.

I tried Version: ImageMagick 6.9.7-4 as well as ImageMagick-7.0.8-35

Can someone help me understand what's going on here?
I don't see anything special in the jpeg files, default quantization tables and so on (checked with jpegsnoop).
Why can't IM estimate the quality?

image32.jpg ... nB7Y4VFPUV

image30.jpg ... N0Zo90jYLf