MRC-Compression (especially with grayscale images)

[ThK89]

Hi!

First of all, I would like to thank you for your great product: I have been an enthusiastic user of PDF-XChange Editor for more than a year. In these times it is more than commendable to offer such a useful program at such a customer-friendly price!

Now, as far as I am concerned, you could increase the usefulness of the software even more by fixing the following problems which I have encountered recently. Both have to do with MRC image compression - an immensely useful technology if you regularly work with scanned material! - but are probably independent of each other:


(1) When I use the function to create a new PDF document (or individual PDF pages) from image files, I never succeed in having grayscale images compressed using MRC: the images are simply imported uncompressed (or so it would appear), and the selection of "MRC" in the Image Compression menu is ignored. It seems to make no difference in which file format the image files are and with which software they were generated. Interestingly, MRC compression works fine when using exactly the same method to create PDF pages from True Color images (but fails again when letting PDF-XChange Editor convert the True Color images to grayscale before compressing them).


(2) If I recompress the images of an already existing PDF file using the "Save as Optimized" function and select MRC, this works with True Color as well as with grayscale images (!) - but only if the file does not contain more than about 10 pages: As soon as the file contains more pages, the optimization process hangs at 15% progress and either freezes completely, or a file can be saved after some time, but it is completely unchanged. So there seems to be some kind of "overflow" here, which makes the program either crash or abort the optimization process.


I imagine that problem (1) might be easier to fix, since here the compression process, as I said, works great on True Color image files, and presumably grayscale images are just not recognized properly for some reason.

If you could find a solution to these problems, I would be very grateful.

Best regards,
Thomas

[Daniel - PDF-XChange]

Hello, ThK89

Regarding item #1, I need to ask first if you are certain that you have enabled the MRC compression options for both format types, as what you have described sounds as though you only enabled the option for True Color, and not Grayscale images:

image.png

Regarding item #2, Could I ask you to please follow the steps here to create a "process dump" next time that the application hangs during this step, so we can investigate what is going on in the background: https://www.pdf-xchange.com/knowle ... cess-dump1

Finally, to help troubleshoot both issues, Could I ask you to please send us a copy of any relevant documents. In this case, at least one of each image type you are working with, as well as the resulting output PDF files. For the freeze issue, a copy of the document before re-processing, a screenshot of the settings you use when re-processing, and then a copy of the saved "after process but no changes made" file. Thank you very much for sending those.

If the files contain sensitive data that should not be on a public forum, you can email us directly via <support@pdf-xchange.com> with a link to this topic.

Kind regards,