identify -verbose to get jpeg quality
Posted: 2019-04-02T04:59:32-07:00
Hi,
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
It seems to be caused by this line:
https://github.com/ImageMagick/ImageMag ... 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
https://drive.google.com/open?id=1SrQr6 ... nB7Y4VFPUV
image30.jpg
https://drive.google.com/open?id=1XAZsk ... N0Zo90jYLf
Cheers
./F
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
https://github.com/ImageMagick/ImageMag ... 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
https://drive.google.com/open?id=1SrQr6 ... nB7Y4VFPUV
image30.jpg
https://drive.google.com/open?id=1XAZsk ... N0Zo90jYLf
Cheers
./F