Planet PDF Forum Planet PDF Forum
  New Posts New Posts RSS Feed - Duplicate Object IDs in PDF?
  FAQ FAQ  Forum Search   Register Register  Login Login


Hi, welcome to the Foxit Planet PDF Forum. If you have PDF or Adobe Acrobat questions then the right place to ask them is here, in this forum.

Duplicate Object IDs in PDF?

 Post Reply Post Reply
Author
TallUser View Drop Down
New Member
New Member


Joined: 14 Jun 2013
Points: 5
Post Options Post Options   Quote TallUser Quote  Post ReplyReply Direct Link To This Post Topic: Duplicate Object IDs in PDF?
    Posted: 14 Jun 2013 at 7:18pm
Hello,

I'm working on an in-house preflighting application we use here and, as a PDF beginner, I tried searching to see if anyone knew whether or not duplicate object IDs are common in PDFs, or if at all possible? There's a bug with the application which reports two identical object IDs, but I doubt it actually has the same ID.
Back to Top
Sponsored Links


Back to Top
aandi View Drop Down
Senior Member
Senior Member


Joined: 07 Jul 2011
Points: 18358
Post Options Post Options   Quote aandi Quote  Post ReplyReply Direct Link To This Post Posted: 14 Jun 2013 at 7:24pm
Yes, it is normal after any incremental update. Obviously only one of them is the one to be used, but which one it is depends on reading the xref tables and xref streams in the correct order (not the order they appear).
Back to Top
TallUser View Drop Down
New Member
New Member


Joined: 14 Jun 2013
Points: 5
Post Options Post Options   Quote TallUser Quote  Post ReplyReply Direct Link To This Post Posted: 14 Jun 2013 at 9:55pm
Originally posted by aandi aandi wrote:

Yes, it is normal after any incremental update. Obviously only one of them is the one to be used, but which one it is depends on reading the xref tables and xref streams in the correct order (not the order they appear).


I just noted that image IDs are being obtained from the XObject ID. I'm looking at the .txt of my pdf and I see a few references to the IDs of the images. My issue is that two different images have the same ID. Is this because they reference the same xref object?
Back to Top
aandi View Drop Down
Senior Member
Senior Member


Joined: 07 Jul 2011
Points: 18358
Post Options Post Options   Quote aandi Quote  Post ReplyReply Direct Link To This Post Posted: 14 Jun 2013 at 10:33pm
I don't know what you mean by "image ID". Images in a PDF don't have IDs, but if you wanted to use the object number as a unique identifier, that would work.

It is entirely possible for the same image XObject to be used in more than one page or even multiple times on the same page. Some PDF optimizing techniques look for common backgrounds etc. and share the same image for them; some page duplication techniques might do the same.

(For reference xref object, read "reference indirect object". A xref object would be something pretty specialist. The xref tables (two kinds) in the PDF list all the indirect objects in the PDF).
Back to Top
Coscript Consulting View Drop Down
New Member
New Member


Joined: 11 Jun 2013
Location: Philadelphia
Points: 9
Post Options Post Options   Quote Coscript Consulting Quote  Post ReplyReply Direct Link To This Post Posted: 15 Jun 2013 at 12:55am
Perhaps, TallUser is asking whether names of the resources can be reused.
They can be reused in different contexts, which can be quite inconvenient for a human reading the file.

Your PDF expert is just a click away.
Back to Top
TallUser View Drop Down
New Member
New Member


Joined: 14 Jun 2013
Points: 5
Post Options Post Options   Quote TallUser Quote  Post ReplyReply Direct Link To This Post Posted: 21 Jun 2013 at 3:03pm
Not only is it annoying for humans, it was breaking one of my applications! Luckily, we don't need clear-cut image names, so I was able to differentiate them enough to prevent the error from occurring.
Back to Top
imhappyyy View Drop Down
New Member
New Member
Avatar

Joined: 31 Jan 2015
Points: 1
Post Options Post Options   Quote imhappyyy Quote  Post ReplyReply Direct Link To This Post Posted: 31 Jan 2015 at 10:06am
I'm looking at the .txt of my pdf and I see a few references to the IDs of the images. My issue is that two different images have the same ID. Is this because they reference the same xref object?
Back to Top
 Post Reply Post Reply
  Share Topic   

Forum Jump Forum Permissions View Drop Down

Forum Software by Web Wiz Forums® version 11.10
Copyright ©2001-2017 Web Wiz Ltd.

This page was generated in 0.015 seconds.