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Berticus

Member

Registered: 2008-06-11

Posts: 731

recovering jpg

I've got this jpg file where the bottom portion is just completely gray. However, in the thumbnail, you can see everything.

When I try to open it with gimp, I get the following error messages:

Corrupt JPEG data: premature end of data segment
Unsupported marker type 0x12

I would've given up on it except for the fact that the thumbnail (viewed in Thunar) had no problem rendering. Everything's there. I tried using this:

ffmpegthumbnailer -i input_image.jpg -o output_repair_0.jpg -s 2970 -q10

But nothing happened. I also tried to use imagemagick, to convert from jpeg to jpeg, but that didn't work either. Any ideas?

hbekel

Member

Registered: 2008-10-04

Posts: 311

Re: recovering jpg

I'd say the file is simply corrupt. The thumbnail you're seeing is either an external thumbnail generated by some application at a time when the image was not (yet?) damaged, or you're seeing a thumbnail image that was directly embedded in the EXIF header of the jpeg file when it was created. In the latter case it's likely that while the image as a whole is corrupt, programs are still able to extract such a thumbnail stored at the beginning of the file.

What's the source of the jpeg image? If it's from a camera, it's very likely that you're seeing an embedded thumbnail. You could use exiftool to check if the image contains such a thumbnail:

$ exiftool -ThumbnailImage image.jpg

joaca_rj

Member

From: Rio de Janeiro, Brazil

Registered: 2009-04-12

Posts: 76

Re: recovering jpg

Anyway, try opening it in various apps... I had some jpgs that appeared corrupted, had thumbnails, and no program could open it.... But gwenview. So, saved each one of them in png and then back to jpg, and done!

karol

Archivist

Registered: 2009-05-06

Posts: 25,440

Re: recovering jpg

hbekel is probably right, it's an embedded thumbnail. You can extract it with jhead but it's low quality so you can't recreate the picture from it.
Maybe http://www.cgsecurity.org/wiki/PhotoRec may help with the corrupted file.