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IMatch Discussion Boards => General Discussion and Questions => Topic started by: Darius1968 on July 26, 2014, 07:03:35 AM

Title: Bits Per Sample (8/16)
Post by: Darius1968 on July 26, 2014, 07:03:35 AM
I'm trying to isolate all my picture files in my database that are 48 bit (16 bits per sample).  How do I do this?  So far, I have a category of 638 images that I know are all 24 bits, but if I try and limit the scope on my metadata to 8 bits per sample, I get only 7 images.  Furthermore, if I modify a layout to display as a footer, the bits per sample, all these 638 images mostly have not text, except for the 7 that have "888".  Why does the EXIF command line processor reveal that all these files are 8 bits per sample, and why doesn't it reflect in the filtering and thumbnail display? 
Title: Re: Bits Per Sample (8/16)
Post by: Mario on July 26, 2014, 08:06:32 AM
I'm not sure that I can follow.

ExifTool delivers the bits per sample in the tag "Main\258\BitsPerSample" which is part of EXIF metadata. IMatch stores whatever ExifTool delivers in this tag and makes the data available to you. You mention the ECP. Do you say that the ECP shows data for your files which is different from the data IMatch has imported?

The easiest way to check all this is obviously to create a data-driven category on the EXIF tag (make sure Other is enabled). This shows you which files have which BPS values, and which files don't. Often you get values like

8 8 8
8 8 8 8
14
16
...
Title: Re: Bits Per Sample (8/16)
Post by: Darius1968 on July 27, 2014, 05:20:19 AM
To answer your question about the ECP, yes it is showing data that is different from what "Main\258\BitsPerSample"reveals when I use it in my footer of my layout.  I did what you suggested, using "Main\258\BitsPerSample" in a data-driven category, making sure "Other" was enabled.  This confirms what I say about the ECP - Better than 90% of the files in my database are 24 bit jpegs that fall under the category of "Other".  When I examine an image in this "Other" category, the field "Main\258\BitsPerSample" gives a null value in my layout, but if I do a "Run (F9)" in the ECP, then it will reveal, "[File]          Bits Per Sample                 : 8". 
Title: Re: Bits Per Sample (8/16)
Post by: Mario on July 27, 2014, 11:20:01 AM
[File] and [Exif] are not the same data.
Attach sample file so I can see myself.
Title: Re: Bits Per Sample (8/16)
Post by: Darius1968 on July 27, 2014, 08:47:20 PM
Okay, I've now attached a jpeg image that registers on the other category and also reveals 8 bps in the context of of [File] and not [Exif]. 

[attachment deleted by admin]
Title: Re: Bits Per Sample (8/16)
Post by: Mario on July 28, 2014, 08:26:51 AM
This file as no EXIF record or other metadata. IMatch does not import made-up values in the [File] category (because this is 99% redundant data which is produced by IMatch anyway). This means you cannot use [File] values produced by ExifTool in IMatch directly.
Title: Re: Bits Per Sample (8/16)
Post by: Darius1968 on July 28, 2014, 09:15:30 AM
I'm having some trouble following this.  If IMatch can't read the data in, how can the ECP tell me it's effectively a 24 bit file? 
Title: Re: Bits Per Sample (8/16)
Post by: Mario on July 28, 2014, 10:05:24 AM
Exiftool produces data in the [File] category. The number of data fields produced depends on the file format. Other fields are file name, extension, folder name etc. IMatch does not import data in the [File] group because IMatch gets the file name, extension etc. from other sources. Importing the [File] tags would be redundant and duplicate information in the IMatch database.

In your very specific case (files without EXIF data but user wants to know the bit depth) this causes the problem you have. I will not change IMatch to import the [File] data for this case, sorry.