The Java and codecLib implementations of the JPEG2000 ImageReader behave differently when the resolution level is provided as an ImageReadParam parameter.

If the lowest resolution level image has dimensions of 16x16 and this lowest resolution image is requested, the Java JPEG2000 ImageReader displays the 16x16 image at the upper left hand corner of the decoded image with dimensions of 512x512. The codecLib JPEG2000 ImageReader displays the decoded image with dimensions of 512x512 as well, however with image data populating the entire 512x512 region. A test case demonstrating this is attached. Simply run the attached test case as 

java JP2Test lena.jp2

The result of the using the codecLib and the Java JPEG2000 ImageReader are displayed in two separate windows, and one can observe that the resulting images are different in these windows, even though the same parameters are provided in both the cases.
  xxxxx@xxxxx   10/7/04 19:35 GMT
Looks also as if the value of the number of resolutions set by the decoder on CompParams.maxlvls is not correct. In tests it was always zero even when the JJ2000 decoder showed it to be 5.
Posted Date : 2005-08-04 01:12:01.0

N/A

The fundamental problem is due to CR 6476371 "codecLib JPEG2000 Decoder delivers lower resolution images with incorrect dimensions". The problem can be fixed by using the JJ2000 reader for lower resolution levels.
Posted Date : 2006-10-13 00:30:25.0