5 Replies Latest reply: Jan 6, 2012 8:02 AM by Dave Merchant RSS

    What (ISO?) document completely specifies the PDF file format?

    DavidW7 Community Member

      Is there ONE (ISO?) document that FULLY specifies the format of a PDF file format? Where to obtain it?

      I need it so I can write a program that will perform some processes on PDF files.

      Thanks

        • 2. Re: What (ISO?) document completely specifies the PDF file format?
          DavidW7 Community Member

          Many Thanks.

           

          Experimenting with Acrobat I have learned the following.

          With Versions upto 9 (included) I had no problem with creating in memory PDF files much larger than 2GB (=2^31) by, for example druging and adding pages from one open file to another (version X have problems even with creation in memory such larger files). It became clear that saving portion of Acrobat fails to save files larger than 2GB.

           

          Therefore I cannot check if Acrobat can OPEN files larger than 2GB.

          Do you happen to know if Acrobat can open such files if and when such files exist?

           

          Do you know if any of those PDF file size limitations is built in into the PDF file format specifications or is it just a problem with the Acrobat implementation?

           

          Thanks

          David

          • 3. Re: What (ISO?) document completely specifies the PDF file format?
            Dave Merchant CommunityMVP

            For all practical purposes there's no file size limit in the ISO PDF specification, however the bit length of internal references means there will be problems at around 10GB. There's also a limit of 2 billion pages (the page count attribute is a 32-bit int).

             

            Distiller won't output more than 32767 pages at a time, but I know cases of archivists working with 100,000-page text files (created by appending thousands of documents, but not in Acrobat).

             

             

            Having said that, the Acrobat Family is 32-bit code, so can only allocate 2GB of process memory. This means you can't perform tasks where an asset larger than the allocated free space has to be retained in RAM, and that includes the save operation. The Acrobat X Family will open an existing file >2GB, and Acrobat X will assemble PDF Portfolios >2GB, but can't save them.

             

            Given that creating >2GB files is a very rare scenario, there are no announced plans to implement x64 flavors of Acrobat or Distiller.

            .

            • 4. Re: What (ISO?) document completely specifies the PDF file format?
              DavidW7 Community Member

              Thanks so mauch.

               

              When you mention: "...open an existing file >2GB..." I wonder upon what is that based? Are you aware of any SW that can create a single PDF file >2GB? By 'creating' I mean also if only by appending multiple files, each smaller than 2GB. Also, are none of the versions before X capable of such opening? (The highest version I have is 9).

              • 5. Re: What (ISO?) document completely specifies the PDF file format?
                Dave Merchant CommunityMVP

                The pdftk library can work with files up to 3.5GB on x86 platforms - we use it to create files for product testing, by appending several embedded videos or appending a file thousands of times with batch scripting. They open fine in Acrobat and Adobe Reader (the videos play, you can search the text, etc), but can't be subsequently saved from within those applications.