FPDF error: This document (testcopy.pdf) probably uses a compression technique which is not supported by the free parser shipped with FPDI

Question

Yes, Exactly the FPDF library supports only PDF version 1.4 & lesser. So to over come from this issue use GhostScript. This script helps to change the PDF versions dynamically.

(1) Download the Ghostscript here.

(2) Install the Ghostscript and define the environment variable PATH.

(3) Then, use the below php code to change the PDF version.

shell_exec( "gswin32 -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dNOPAUSE -dQUIET -dBATCH -sOutputFile=".$new_pdf." ".$old_pdf.""); 

(4) Now we get PDF with version 1.4 as output, then continue with FPDF.

Enjoy!

I had the same issue that PDFMerger does not work with certain PDF. It seems that Adobe keep updating compression way of pdf extension.

I found solution with Chrome.

1. Open the PDF file(which does not work with PDFMerger) with Chrome
2. Right Click and Print
3. Change destination as [Save as PDF]
4. This exported PDF file is compatible with PDFMerger

The file needs to be PDF 1.4 (Acrobat 5) or lower. If you have Adobe Acrobat Pro you can change this with Document->Decrease File Size.

Looking through the answers so far, I wasn't able to resolve the issue. Here's why and you may have the same issue so this answer would be invaluable to you too.

I did not have access to acrobat, so I couldn't downgrade the version of the original PDF. I wasn't in a position to purchase the newer version of the library which has upgraded encryption.

In the end I used an online PDF converter to downgrade my PDF file to version 5 (1.4)

If you are not able to find one, here's a link for completeness.

https://docupub.com/pdfconvert/

(bear in mind that the contents of a link may change)

Here is my answer from another topic:

"It can be overcome by re-saving the template and change compression type. In Adobe Acrobat Pro go to File->Save As->Optimised PDF-> Popup left list - Clean Up, Object Compression Options -> Change to "Compress document structure" -> OK to save"

Ref. Editing password protected pdfs with fpdi

For those that don't have any of the pro versions of Acrobat:

I was having this problem with new versions of Word when trying to use the Office functionality to save to a PDF. It seems the PDF conversion tool supplied in Office is using the newer formats. Here's how I fixed it.

• Install NitroPDF free version (May work with another free PDF creator that can be downloaded)
• Go to the Word document and select 'Print'.
• In the print options, instead of your printer, select 'Nitro PDF Creator (Reader 3)' or whatever the current version is.
• A dialog box will open and allow you to select where to save the PDF.

The version saved was able to be opened by FPDF.

Hope it helps