Hi, 

As you noted, it sounds like the issue is that the PDF has embedded 
JPEG2000 images.  That error seems to be thrown by PDFBox, which is the 
library DSpace uses to index and create thumbnails from PDFs (by default).

It sounds like the issue is that PDFBox won't create thumbnails for 
JPEG2000 images unless you install more libraries.  Here's what looks like 
the solution from 
StackOverflow. 
https://stackoverflow.com/questions/57707735/how-to-fix-cannot-read-jpeg2000-image-java-advanced-imaging-jai-image-i-o-to
  
 You'd likely have to add additional dependencies to DSpace's main 
"pom.xml" (alongside the "org.apache.pdfbox" dependencies already listed 
there).  

That'd require rebuilding / redeploying DSpace to ensure these new 
dependencies are installed on your backend.  I'm not sure if it'd work 
immediately after rebuilding, or if more changes would be needed. (As I've 
never tried this before and not yet seen this error.)

Or, alternatively, you could try to use the ImageMagick Media Filters, 
which can also create thumbnails from PDFs.  In this situation you'd 
disable the default "PDFBox JPEG Thumbnail" filter and enable ImageMagick 
instead as described 
here: https://wiki.lyrasis.org/display/DSDOC7x/ImageMagick+Media+Filters  
 That PDF thumbnail converter might have an easier time with JPEG2000 
images (I admit though that I haven't tested it).

Tim

On Thursday, November 16, 2023 at 6:53:11 AM UTC-6 tif...@gmail.com wrote:

> Nobody had such a problem?
>
> niedziela, 12 listopada 2023 o 18:08:51 UTC+1 Technologiczny Informator 
> napisał(a):
>
>> Hello everyone,
>>
>> DSpace 7.6 users reported an issue with an empty thumbnail of the 
>> deposited PDF file. Analysis of the problem showed an error in the log - 
>> several entries in a row about the content:
>>
>> ERROR unknown unknown org.apache.pdfbox.contentstream.PDFStreamEngine @ 
>> Cannot read JPEG2000 image: Java Advanced Imaging (JAI) Image I/O Tools are 
>> not installed
>>
>> As I understand it, the deposited PDF file contains images in JPEG2000 
>> format and therefore DSpace has a problem generating the correct thumbnail.
>>
>> How can we get out of this situation? Thank you in advance for any 
>> suggestions.
>>
>> Regards,
>> Mariusz
>>
>

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