Embedded image extraction (encoding)

[itsjustvenky]

Hi Everybody,

I have a question regarding how the exiftool extracts embedded image.
I have a INDD file which has two pages in it.So the xmp data has two embedded thumbnails.
So I tried extracting metadata from file INDD file using "exiftool -tagsfromfile test.indd output.xmp", but this command is extracting bad embedded image. I have tool (code) which extracts embedded image from xmp packet as it is.

Now I tried "exiftool -tagsfromfile test.indd -xmp output.xmp" (with -xmp option), now I am getting proper embedded image (jpeg it is).

So can somebody please let me know what is happening with "-xmp" and without "-xmp" option.

I have another question. If I use "-xmp" in with -tagsfromfile, do I loose any metadata ??

please let me know.

thanks
Venkatesh

[Phil Harvey]

Hi Venkatesh,

When you add -xmp, the XMP metadata is copied as a block.  Otherwise the tags are copied individually. 

If you send me a sample INDD with this problem, I'll take a look.  My email is philharvey66 at gmail.com

- Phil

[itsjustvenky]

Hi Phil,

Thanks for your reply. I just emailed you the INDD file. Please do let me know what might be the issue.

Regards
Venkatesh

[Phil Harvey]

Hi Venkatesh,

I got the INDD file.  It contains two PageImage previews.  The previews are copied just fine to the XMP file using either command.  Without -xmp in the command, the Base64 data is split into lines of 60 characters, which is perfectly valid.  You can extract the previews from either file with this command:

exiftool -W %d%f_%t%c.%s output.xmp

The extracted JPEG images are identical with or without -xmp in the command.

So as far as I can tell, there is nothing wrong with ExifTool.

The problem must be in your tool that extracts the embedded image from the xmp.

- Phil

[itsjustvenky]

Hi Phil,

Thank you very much. I didn't know that without -xmp option the embedded image data is not decoded and hence when the image data is extracted I was getting bad image.
Its just I was not using correct option for extraction.

-Venkatesh