Conversion of grayscale JPEG-XR images produces distorted results

Bug #1720638 reported by John Howell on 2017-10-01
This bug affects 1 person
Affects Status Importance Assigned to Milestone

Bug Description

The KFX format uses grayscale JXR images within books delivered to e-ink Kindle devices. I have tried converting some of these images within calibre and the resulting images are distorted and cropped.

I have found that removing the "-c 0" argument when invoking JxrDecApp fixes the problem and results in correct conversion of these images. (The code that does this is load_jxr_data() in calibre.utils.img.)

I will attach a zip containing three files to demonstrate this problem:

"statue.jxr" is the original grayscale JXR image.

"statue.tif" is a good conversion created by running:
 JxrDecApp-calibre -i statue.jxr -o statue.tif

"statue2.tif" is a badly distorted conversion created by running :
 JxrDecApp-calibre -i statue.jxr -o statue2.tif -c 0

I suggest that the "-c 0" option not be used when invoking JxrDecApp.

John Howell (jhowell-o) wrote :

Fixed in branch master. The fix will be in the next release. calibre is usually released every alternate Friday.

 status fixreleased

Changed in calibre:
status: New → Fix Released
John Howell (jhowell-o) wrote :


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