[gphoto-bugs] [ gphoto-Bugs-1548739 ] thumbnails on CANON DSRL don't show

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Bugs item #1548739, was opened at 2006-08-29 19:00
Message generated for change (Comment added) made by d98_ama
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Category: libgphoto2
Group: None
Status: Open
Resolution: None
Priority: 5
Submitted By: ggg (gerhardkgmx)
Assigned to: Hubert Figuiere (hfiguiere)
Summary: thumbnails on CANON DSRL don't show

Initial Comment:
In the camera GUI, only jpg file thumbnails are shown 
and no thumbnails are shown in the cr2 files. This is 
tested with EOS 350D and 30D. 
 
 Furthermore there are no image properties or exif 
data available when selecting the appropriate 
sidebars. Once the cr2 are downloaded all is well, 
thumbnails are visible and exif data is complete. 
Also, when the CF card is accessed through a card 
reader, all is well.
 
 I presume the two bugs has the same root cause, 
since the exif data cannot be read, the embedded 
thumbnail is not available either. 
 
 The following error messages are produced in a shell 
from which digiKam was launched: 
 
 digikam: Cannot parse EXIF metadata using Exiv2 
 digikam: [static Digikam::DImg::FORMAT 
Digikam::DImg::fileFormat(const QString&)] Failed to 
open file 
 digikam: [static Digikam::DImg::FORMAT 
Digikam::DImg::fileFormat(const QString&)] Failed to 
open file 
 digikam: Size of Exif metadata from camera = 20 
 digikam: Exif header found at position 0

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Comment By: Anders Magnusson (d98_ama)
Date: 2006-09-20 23:07

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I have a similar problem with a Canon EOS 30D, but I don't
know if it is the exact same problem.

When I plug in my Camera GNOME pops up a wizard that lets me
import my photos. The Camera is identified correctly, but
the wizard says that there are no images available.
I get the same thing when I try to import my pictures using
gthumb.


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Comment By: Marcus Meissner (marcusmeissner)
Date: 2006-08-30 09:25

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Well, the PTP transfer usually includes a pointer the 
thumbnail (for JPEGs), which we use. 
 
I have investigated a bit, and a CR2 file has a TIFF 
structure, which in turn has a JPEG preview embedded inf 
IFD1. 
 
tiffdump blub.cr2: 
.... 
Directory 1: offset 390952 (0x5f728) next 400497 (0x61c71) 
JPEGInterchangeFormat (513) LONG (4) 1<391464> 
JPEGInterchangeFormatLength (514) LONG (4) 1<9033> 
... 
 
What we could do in libgphoto2 is partial downloads to 
retrieve the header parts and to extract this JPEG as 
preview. 

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Comment By: ggg (gerhardkgmx)
Date: 2006-08-29 21:56

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It is digiKam UI
But it is definitely a gphoto2 problem, gtkam UI show the 
same fault as digiKam and Gilles Caulier thinks it is 
gphoto2.

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Comment By: Hubert Figuiere (hfiguiere)
Date: 2006-08-29 21:48

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btw which camera UI ? because what you describe is Digikam
and digikam is not our problem.

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Comment By: Hubert Figuiere (hfiguiere)
Date: 2006-08-29 21:47

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I think this has already been discussed. In PTP it looks
like we don't fecth the thumbnail from the .cr2 file on Canon.


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Comment By: Marcus Meissner (marcusmeissner)
Date: 2006-08-29 21:02

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can you please attach a sample cr2 file? thanks. 

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