Embedded Thumbnail Not Shown

[pixelperfecto]

Hi,

I have the default setting of Use Embedded thumbnail enabled, yet the embedded thumbnail is not showing for my camera's pictures. I do not have the suboption Create thumbnail from original image if embedded is smaller than thumbnail size enabled. I have thumbnail caching disabled.

Here is an example problematic image:

http://izjuag.bay.livefilestore.com/y1p ... 0(006).jpg

I am running XnView 1.96 on Windows XP SP2.

Thanks for looking at this.

[Clo]

pixelperfecto

Hello ! Welcome aboard !

• It seems you are right : Here, the embedded thumb nail is not shown by an overlay icon on the thumb nail,
despite it's alright in the image, that I can see from the Exif data…

Kind regards,
Claude
Clo

[xnview]

yes right

[pixelperfecto]

Hello,

Thanks everyone for confirming this odd behavior.

[XnTriq]

[quote="jhead -st "thumbnails\&i" *.jpg"]

Code: Select all

Nonfatal Error : '2008.11.06 (006).jpg' Illegal number format 32 for tag 010f
Created: 'thumbnails\2008.11.06 (006).jpg'

[/quote]

[pixelperfecto]

So, if there is an error with the EXIF, what does that mean? Is it a problem with the file, camera, or what? I can view the embedded thumbnail fine in WildBit Viewer (http://www.wildbit-soft.fi/software.html). The file I provided is an original, but I have tried rebuilding the thumbnail in both XnView and BetterJPEG, yet the thumbnail still will not show in XnView.

[XnTriq]

Do you know for sure that the photo is coming straight from the camera and hasn't been altered?

Code: Select all

*** Marker: COM (Comment) (xFFFE) ***
OFFSET: 0x00003415
Comment length = 18
Comment=Camera .MISC

Code: Select all

NOTE: JFIF COMMENT field is known software
Based on the analysis of compression characteristics and EXIF metadata:

ASSESSMENT: Class 1 - Image is processed/edited

[pixelperfecto]

Yes, the image is coming straight from the camera and hasn't been altered. I simply copied, renamed, and uploaded it, none of which should edit the file. All the images are the same way from the camera; they each have a JPEG comment. I have tried the programs jhead and JPEGsnoop on the others and they too come up with your results. I even tried them on images on the memory card itself. Here is an image uploaded directly from the memory card with its original camera name:

http://izjuag.bay.livefilestore.com/y1p ... DV0098.JPG

Is it possible that the camera's software has a common signature to other editing software and is showing a false positive here? Or is the JPEG non-compliant to standards or using some other? The camera is an Aiptek Pocket DV3100+.

Can I fix these files, or will XnView in the future, ever be able to read them in their current state? Like I said, WildBit Viewer has no trouble, so is XnView and jhead simply too strict?

[XnTriq]

It seems to me that the camera's firmware doesn't produce standards-compliant JPEGs (missing APP0 marker)

Filename: [X:\PCDV0098.JPG]
Filesize: [810171] Bytes

Start Offset: 0x00000000
*** Marker: SOI (xFFD8) ***
OFFSET: 0x00000000

*** Marker: APP1 (xFFE1) ***
OFFSET: 0x00000002
length = 7984
Identifier = [Exif]
Identifier TIFF = x[49 49 2A 00 08 00 00 00 ]
Endian = Intel (little)
TAG Mark x002A = x[002A]

EXIF IFD0 @ Absolute x[00000014]
Dir Length = x[000A]
[ImageDescription ] = Camera
Offset to Next IFD = [0000008F]

Formally, the Exif and JFIF standards are incompatible. This is because both specify that their particular application segment (APP0 for JFIF, APP1 for Exif) must be the first in the image file. In practice, many programs and digital cameras produce files with both application segments included. This will not affect the image decoding for most decoders, but poorly designed JFIF or Exif parsers may not recognise the file properly.

The JFIF specification states that the APP0 marker should follow immediately after the SOI marker in a JPEG file. Here is an example of the beginning of a valid JPEG FIF file:

Code: Select all

FF D8 FF E0 ...

In this example, immediately following the SOI marker is the APP1 (FF E1) marker that describes Exif information (i.e. shutter speed, aperture, and camera model). The APP0 marker is nowhere to be found! Applications and services such as Apple's ColorSync and iView MultiMedia Pro depend on JPEG files conforming to the JFIF specification for certain functions, such as embedding ICC Color Profiles.

[pixelperfecto]

XnTriq,

Thank you very much for the helpful information and analysis. I hope in the future that XnView can be more JPEG-DCF-aware, since this is a popular format today.

[marsh]

>pixelperfecto
If you only care about readable thumbnail, they can be quickly regenerated. I just tried this on thousands of images (not suitable for everyone, but maybe worth a test):
With jhead, transplant a known good EXIF(with thumb) to images, then use XnView to recreate the thumbnails to match.
Ex:
jhead -te good.jpg target.jpg
Menu>Edit>Metadata>Recreate EXIF thumbnail

[pixelperfecto]

marsh,

Thank-you. This is an interesting solution that certainly would work. Only thing is, the EXIF wouldn't match and would be unfortunate, misleading, and confusing. I am trying to get an overview of originals quickly over USB, so the embedded thumbnails are quite helpful. But, I wouldn't want to really make an entire duplicate set of my images. It would be easier to use a program like JPEG-JFIF Repair, but it is only available for the Mac. I guess I will either have to use a different viewer, or wait for XnView to catch up.

[XnTriq]

pixelperfecto,

this software might also be helpful in finding a solution:

Phil Harvey: ExifTool
A Perl application and library for reading and writing EXIF, GPS, IPTC, XMP, makernotes and other meta information in image, audio and video files. For Windows, Mac OS X, and Unix systems.

exiftool '-ThumbnailImage<=thumb.jpg' dst.jpg

• Set the thumbnail image from specified file (Note: The quotes are neccessary to prevent shell redirection).

Stuffware: Photo Studio
Multi-purpose imaging application. View, edit, manage, download and create digital images with this flexible and easy to use tool.

Additionally Photo Studio is a useful tool for examining and manipulating the contents of additional data stored along with your images, supporting a wide range of formats from EXIF/DCF and CIFF (as saved by many digital cameras) through JFIF to the often used Photoshop extensions.

[pixelperfecto]

[pixelperfecto]

Thanks!