[IPP] PDF Raster and IPP Scan

[IPP] PDF Raster and IPP Scan

Kennedy, Smith (Wireless Architect) smith.kennedy at hp.com
Tue Sep 5 21:57:03 UTC 2017


Is the XML metadata addition being used as a replacement for what might be conveyed over IPP as IPP attributes (e.g. "job ticket" type info)?


> On Sep 5, 2017, at 6:44 AM, Michael Sweet <msweet at apple.com> wrote:
> 
> Paul,
> 
> As this is a strict subset of PDF and IPP Scan requires PDF support, nothing needs to be added unless you want the Client to be able to explicitly ask for a particular subset of PDF...  We could add a pdf-versions-supported keyword, but that is strictly informative...
> 
> That said, this subset is almost exactly the same as the PDF/is specification the PWG published 13 years ago:
> 
>    http://ftp.pwg.org/pub/pwg/candidates/cs-ifxpdfis10-20040315-5102.3.pdf
> 
> The main differences appear to be:
> 
> 1. No JBIG2 support (?!?)
> 2. Different file format identification methods: PDF/is adds a new object, while PDF Raster uses a comment in the trailer.
> 3. PDF Raster supports encryption while PDF/is does not, but that doesn't really matter - PDF encryption is a joke because key generation is weak.
> 4. PDF Raster adds an XML (Adobe XMP) metadata object.
> 
> Both PDF/is and PDF Raster support banding, digital signing, and incremental/streamed writing.  Both also support the same bi-level, grayscale, and RGB color color spaces and bit depths.
> 
> The PDF Raster spec claims that it can be consumed by a simple parser, but I don't see how given that images can be banded - you will still need to implement a minimal page stream interpreter along with random access to the image objects.
> 
> Finally, it looks like a PDF writer could generate a PDF file that conforms to BOTH PDF/is and PDF Raster - thus an IPP Scan implementation could (as part of the general PDF support requirement) produce PDF scan files compatible with both standards.  But again, I don't think we need to update IPP Scan for this...
> 
> 
> 
>> On Sep 1, 2017, at 8:34 AM, Paul Tykodi <ptykodi at tykodi.com> wrote:
>> 
>> Hi,
>> 
>> I saw this announcement this morning.
>> 
>> Should we consider adding support for this format in IPP Scan?
>> 
>> http://www.prweb.com/releases/2017/08/prweb14644230.htm
>> 
>> Best Regards,
>> 
>> /Paul
>> 
>> Sent from my iPhone
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> 
> _________________________________________________________
> Michael Sweet, Senior Printing System Engineer
> 
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