ExifTool Forum

General => Metadata => Topic started by: neebah on December 29, 2015, 07:17:03 PM

Title: Unknown APP 13 item
Post by: neebah on December 29, 2015, 07:17:03 PM
I recently did a WIC query on a photo and found two bits of information that I haven't been able to decipher.  EXIFTOOL doesn't provide any insight. 

I'm not sure how familiar you are with WIC queries (microsoft provides some info in general, but not in all.  Here are the WIC query strings

"/app13/{ushort=0}/{ulonglong=88271599437876}/{}"
"/app13/{ushort=0}/{ulonglong=88271599437877}/{}"

The first four bytes of the information in these queries if translated to ASCII spell out PHUT
Title: Re: Unknown APP 13 item
Post by: Hayo Baan on December 30, 2015, 01:35:19 AM
What is a WIC scan and how did you find these strings?
Title: Re: Unknown APP 13 item
Post by: neebah on December 30, 2015, 01:48:27 AM
Windows Imaging Component.  In .NET programming one can acquire image metadata by performing a WIC query.  It is possible to perform a query on all available metadata.  When I did so this string popped up.  If you look up Native Metadata Query on google you'll find out more info. 
Title: Re: Unknown APP 13 item
Post by: Phil Harvey on December 30, 2015, 10:11:58 AM
PHUT is a signature that I have seen for Photoshop IRB resources, and APP13 is the one that Photoshop uses for IRB resources.  So I suspect this is IRB format, but with a different header.  Send me a sample and I'll take a look.  (philharvey66 at gmail.com)

- Phil
Title: Re: Unknown APP 13 item
Post by: StarGeek on December 30, 2015, 12:05:13 PM
There's a sample image in this github thread (https://github.com/drewnoakes/metadata-extractor/issues/125).
Title: Re: Unknown APP 13 item
Post by: neebah on December 30, 2015, 05:29:03 PM
sent to your email
Title: Re: Unknown APP 13 item
Post by: Phil Harvey on December 30, 2015, 05:51:23 PM
I got your sample.  I thought you were talking about an unknown APP13 segment with a "PHUT" header.  But this is a standard Photoshop APP13 segment which contains a PHUT IRB with a tag ID of 0x0835.  ExifTool reads this, but this tag ID is not known.  The values is all zeros anyway, so not useful information.

- Phil
Title: Re: Unknown APP 13 item
Post by: neebah on December 30, 2015, 06:47:39 PM
What is a PHUT IRB?
Title: Re: Unknown APP 13 item
Post by: Phil Harvey on January 01, 2016, 01:04:28 PM
It is a photoshop Image Resource Block with a "PHUT" signature instead of the usual "8BIM".

- Phil