Merged pdf is bigger than sum of merged files

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Hi,
I'm using Quick pdf library 8.14. with c#
I noticed that when i merges some pdf files (with MergeFileListFast or MergeFileList), the result is bigger than sum of merged pdf size.
It's about 50% more.

I opened then saved the file with acrobat and the size decreased significatively. 

So, i looked into the merged pdf with notepad++, i compared it with the one saved by acrobat and i found plenty of 'null' objects that were not present in the pdf saved by acrobat :

40 1 obj
null
endobj

where 40 1 is a variable sequence

I also found this kind of line, which doesn't exists in acrobat saved file :

0002439380 00001 n 

where 0002439380 is a variable sequence.

I looked into originals merged pdf files and i didn't find any occurency of the first pattern (obj null endobj). I found The second one but less than in the merge result.

I decided to delete all line that matched these patterns and the resulting pdf file was of the correct size (sum of merged ones) and not corrupted when opened in acrobat.

Is there a reason for quick PDF to add this "null object" when merging pdf files?

Thanks for any help.

Edited by SebSil - 11 Apr 12 at 4:27PM

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SebSil Members Profile Find Members Posts Beginner Joined: 25 Aug 10 Location: France Status: Offline Points: 3	Post Options Post Reply Quote SebSil Report Post Thanks(0) Quote Reply Topic: Merged pdf is bigger than sum of merged files Posted: 11 Apr 12 at 4:26PM
	Hi, I'm using Quick pdf library 8.14. with c# I noticed that when i merges some pdf files (with MergeFileListFast or MergeFileList), the result is bigger than sum of merged pdf size. It's about 50% more. I opened then saved the file with acrobat and the size decreased significatively. So, i looked into the merged pdf with notepad++, i compared it with the one saved by acrobat and i found plenty of 'null' objects that were not present in the pdf saved by acrobat : 40 1 obj null endobj where 40 1 is a variable sequence I also found this kind of line, which doesn't exists in acrobat saved file : 0002439380 00001 n where 0002439380 is a variable sequence. I looked into originals merged pdf files and i didn't find any occurency of the first pattern (obj null endobj). I found The second one but less than in the merge result. I decided to delete all line that matched these patterns and the resulting pdf file was of the correct size (sum of merged ones) and not corrupted when opened in acrobat. Is there a reason for quick PDF to add this "null object" when merging pdf files? Thanks for any help. Edited by SebSil - 11 Apr 12 at 4:27PM

Ingo Members Profile Find Members Posts Moderator Group Joined: 29 Oct 05 Status: Offline Points: 3530	Post Options Post Reply Quote Ingo Report Post Thanks(0) Quote Reply Posted: 11 Apr 12 at 7:20PM
	Hi! Yes... that's strange. You should post your thread on the official support page. There you can upload your pdf, too. Make a version -before- and one version -after-: http://www.quickpdflibrary.com/support/support-query.php Cheers and welcome here, Ingo Edited by Ingo - 13 Apr 12 at 11:48AM

SebSil Members Profile Find Members Posts Beginner Joined: 25 Aug 10 Location: France Status: Offline Points: 3	Post Options Post Reply Quote SebSil Report Post Thanks(0) Quote Reply Posted: 13 Apr 12 at 11:41AM
	Hi Ingo, Thanks for your reply. I 've just post my thread onto QPDF official Support page. Thanks,

edvoigt Members Profile Find Members Posts Senior Member Joined: 26 Mar 11 Location: Berlin, Germany Status: Offline Points: 111	Post Options Post Reply Quote edvoigt Report Post Thanks(0) Quote Reply Posted: 23 Apr 12 at 1:24PM
	Hi SebSil, it would be nice, to see here the answer from QPDF, if there is one. Thanks in advance, Werner

SebSil Members Profile Find Members Posts Beginner Joined: 25 Aug 10 Location: France Status: Offline Points: 3	Post Options Post Reply Quote SebSil Report Post Thanks(0) Quote Reply Posted: 23 Apr 12 at 1:29PM
	Hi edvoigt, Here's the QPDF answer: "The first PDF in the list contains thousands of unused entries in the xref table and QPL as creating the 'null' entries just to make sure the PDF stream is correct according to the PDF spec. I need to talk to the lead programmer to see what can be done. We are looking to add a PDF cleanup feature in an upcoming release of QPL". I haven't answered yet, but i have the same issue with most of pdf files i'm working with (from differents providers).

edvoigt Members Profile Find Members Posts Senior Member Joined: 26 Mar 11 Location: Berlin, Germany Status: Offline Points: 111	Post Options Post Reply Quote edvoigt Report Post Thanks(0) Quote Reply Posted: 23 Apr 12 at 1:43PM
	Hi, a such cleanup would be very usefull, because there are a lot of PDFs in the wild, which are build in strange kinds. So I hope, the QPDF-people can make it. Werner