Jpeg - embedded thumbnails

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August 21st, 2011, 09:33 PM
Aniskin

Jpeg - embedded thumbnails

Some time ago I started examining metadata in jpeg especially embedded thumbnails. And I found many interesting things about it. Do you know that some photo cameras add additional thumbnail with resolution up to 640x480 px. It can be very useful in situations when you found broken image. For example:

1) We found photo image with car, but there is no car number: Photo.

2) We can see small thumbnail in exif segment, but number so tiny: Exif thumbnail.

3) But we can see big thumbnail in additional FPRX segment with numbers: FPRX thumbnail.

4) Profit!

I found about 10 different proprietary segment types which can contain additional thumbnail. Also jpegs can contain embedded audio. And I don’t know any software (except my) which can read it. Is I am wrong?
August 22nd, 2011, 01:48 AM
D0pp139an93r

EXIF data?

Old.
August 22nd, 2011, 04:37 AM
Aniskin

Quote:

Originally Posted by D0pp139an93r

EXIF data?
Old.

I agree that exif is very old theme, but what about fprx? Could you give me a link to the app which can show embedded thumbnail in fprx?
August 22nd, 2011, 02:28 PM
nihil

Yes, you are wrong. Obviously if the data could not be read it would serve no function and wouldn't be there.

Try this:

http://owl.phy.queensu.ca/~phil/exiftool/

Very useful for sanitising metadata as I recall ;)

You might also look at the latest version of xnView.

There is nothing magical about FlashPixReady thumbnails. Their original purpose is to permit reasonable quality previews on larger screens.

Basically the old Exif file was restricted to 64KB which is a single APP1 segment, whereas FPXR lets you use multiple APP2 segments depending on the whim of your equipment manufacturer.
August 25th, 2011, 06:04 PM
Aniskin

Quote:

Originally Posted by nihil

Try this:

http://owl.phy.queensu.ca/~phil/exiftool/

Very useful for sanitising metadata as I recall ;)

I am fully agree with you. It is great tool, and all results of my research were sent to Phil. But in case of non jpeg-based thumbnail formats Phil answered me:

Quote:

Originally Posted by Phil

Current I only extract thumbnails in standard image formats. I don't do image processing so I don't convert other data formats.

So many of thumbnail types ignored by exiftool.

And what about user friendly tool with gui?

Quote:

Originally Posted by nihil

You might also look at the latest version of xnView.

I can confirm that xnView show FPRX thumbnails in case of broken image, but... there are several FPRX types exist in real photos, and xnView dont show all of them.

Quote:

Originally Posted by nihil

Basically the old Exif file was restricted to 64KB which is a single APP1 segment, whereas FPXR lets you use multiple APP2 segments depending on the whim of your equipment manufacturer.

In some case APP4 segment is used.
August 28th, 2011, 02:54 PM
nihil

Hi, for a user friendly GUI for the Exif tool please try BogdanH's offering:

http://u88.n24.queensu.ca/exiftool/f...ic,2750.0.html

Quote:

So many of thumbnail types ignored by exiftool.

You surprise me there, do you have examples? I can understand that there would be older, legacy types particular to a model and manufacturer of camera, but I would have expected standardisation to meet the requirements of editors and publishers?

Quote:

there are several FPRX types exist in real photos, and xnView dont show all of them.

Could we have some examples please?.................you will have realised by now that it has been quite some time since I last looked at this subject? :D

Cheers
August 28th, 2011, 07:57 PM
Aniskin

Quote:

Originally Posted by nihil

http://u88.n24.queensu.ca/exiftool/f...ic,2750.0.html

Thanks, I will look it.

Quote:

Originally Posted by nihil

You surprise me there, do you have examples?

I will prepare them and will publish some later.

Quote:

Originally Posted by nihil

Could we have some examples please?.................you will have realised by now that it has been quite some time since I last looked at this subject? :D

5 samples from Phil`s collection: http://www.4shared.com/file/O9Xsoosy/FPXR.html. I have cut several bytes at the end of each file and so they become broken.