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H
Hitz_M
Inspiring
November 2, 2009
Question

XMP metadata lost from PNG files after saveing

  • November 2, 2009
  • 1 reply
  • 1393 views

Hello,

i am using Photosop CS3 SDK. through my plug-in I put some metadata in the file using XMP SDK 4.4.2.

For PNG files, if the file is modified and saved, all the XMP metadata is lost from the file.

The following steps are being done.

1. Put some metadata in PNG file using SXMPMeta::SetProperty and SXMPMeta::AppendArrayItem

2. modify the file (changed brightness, contrast, flattened the image).

3. Save this file.

After saving all the xmp metadata is lost from the PNG file. This works for all other formats.

What can be wrong that I am doing?

Is there any other way to put XMP metadata in file?

Thanks,

Hitesh

This topic has been closed for replies.

1 reply

Chris Cox
Chris Cox
Legend
November 2, 2009

That's probably because PNG doesn't save or read XMP metadata.

There really aren't standards for metadata in PNG. (though a few products have tried adding it in ad-hoc ways, without documenting their efforts)

A
Ardfry
Participating Frequently
November 2, 2009

Doesn't Bridge do this?

Isn't this documented in the XMP spec (XMP in PNG)?

Chris Cox
Chris Cox
Legend
November 2, 2009

It's not exactly documented.

There were a couple of incompatible drafts, and now we have different apps storing data in different places.

We've asked for clarification (and some cleanup), but haven't gotten anywhere yet.

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