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I found a similar question that involves Acrobat, but in this case the PDF was made with a combination of MS Word and CenoPDF v3, with which I'm unfamiliar. Additionally the PDF is version 1.3. I'd like to decompress it, to see its low-level workings and make some changes. It's easy with GhostScript's -dCompressPages=false parameter, but that simultaneously strips all the fill-in form functionality. Is there a method for decompressing the file while leaving everything else intact? A quick search of the docs for tcpdf and fpdi (cited in the link) didn't reveal a compression option.

tao
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  • *to see its low-level workings* - I'd propose using a PDF browser software instead. – mkl Aug 19 '14 at 13:18

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Ghostscript and pdfwrite isn't a good combination. The PDF file you get out is NOT the same as the one you put in. This is because of the way that Ghostscript and pdfwrite work; the input is fully interpreted to a sequence of graphics primitives, which is sent to the Ghostscript graphics library. These are then sent to the requested device, most devices then render the result to a bitmap, but the pdfwrite family reassemble those graphics primitives int a new PDF file.

Note that the contents of the new PDF file have no relationship to the original, other than the appearance when rendered. Ghostscript and pdfwrite do maintain much of the non-marking content of PDF files such as hyperlinks and so on (which obviously don't get turned into graphics primitives), by interpreting them into pdfmark operations (an extension to the PostScript language defined by Adobe). However, even if Ghostscript and pdfwrite maintained all this content, the resulting PDF file wouldn't be the same as the original one decompressed....

There are tools which will decompress PDF files, and I would recommend one of our other products, MuPDF. A part of this is mutool, and "mutool clean -d in.pdf out.pdf" will decompress pretty much everything in a PDF file

KenS
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QPDF can decompress PDF documents (among other things). I used this tool in the past and it preserved forms and data.

The tool has some issues with large PDFs (can take too much time and memory for decompression). The tool can produce incomplete output (with warnings in console) for some partially broken / nonstandard PDFs.

Bobrovsky
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