Is there a reliable way to determine if a PDF was generated from a Powerpoint file?

Question

Like the title says. Reason I ask is that we're converting PDFs to formatted ASCII text (using pdftotext) and only want to display the ones that look reasonably sane.

PPT files tend to have text over images, diagonal text and others things that don't translate to ASCII very well, so we'd like to filter them out if we can.

Answer 1

The creating application of a PDF is listed in its XMP metadata. You can see this quite easily in Acrobat 9 (and I believe earlier): go to File > Properties, click Additional Metadata..., then go to Advanced and it's listed under both XMP Core Properties and PDF Properties:

xmp:CreatorTool: Microsoft PowerPoint
pdf:Creator: Microsoft PowerPoint

I'm guessing you want to find this programatically, so you'll need to find a library to read this metadata that works with your language. Here is a list of some XMP tools.

Answer 2

Short answer:

No, I don't think so.

Long answer:

No, I don't think so, because there are may ways to convert a PowerPoint file to pdf, for example Adobe Acrobat and PDFCreator and many many others. It's up to the converters to embed specific information in the PDF file, even if you find a way to detect PowerPoint-source pdf from one convert, the same method may not work for another.

Even longer answer:

No, I don't think so, because of the reasons described in the "long answer". And I don't think detecting the source of the PDF is the best approach to the problem you are trying to solve. Not just PowerPoint produces overlapped text and images. I think it's much better to detect the actual layout of the PDF file. If there are overlay of image and text, then you do some filtering or pre-processing to cater for that.