low-res thumbnail in exported jpeg is incorrect.
I appears that when exporting to jpeg, the low-res thumbnail found in the exif data is a thumbnail of the original image, not of the final image. It's very obvious when a lot of cropping has been done, the picture has been converted to b/w, etc etc etc.
As an example, see the attached image, which is quite heavily cropped and is converted to b/w.
Merge pull request #921 from tomtor/k-x-preview
[Bug #9017] Fix output of embedded preview in Pentax (k-x) DNG
#2 Updated by Richard Levitte over 7 years ago
Sure. They're all uploaded here: http://richard.levitte.org/~levitte/for-darktable/
#3 Updated by Ulrich Pegelow about 7 years ago
- % Done changed from 20 to 10
- Target version set to Future
- Priority changed from Medium to Low
- Status changed from Incomplete to Confirmed
- Category set to General
In fact darktable does not write thumbnails into exported files itself. We seem to inherit thumbs from the input RAW.
I assume that some image viewers have problems as they might take the (then incorrect) thumb for overviews rather
than using the full jpg.
Also darktable seems to stumble over the thumbnail when importing its own generated jpegs:
"Warning: Directory Thumbnail, entry 0x0201: Data area exceeds data buffer, ignoring it."
We need to either find a way to reliably eliminate thumbs (from the exif data) or write our own ones.
#4 Updated by Henrik Andersson about 7 years ago
- Assignee set to Henrik Andersson
Darktable should discard the thumbnail when fetching the exif blob, this is done
by discarding specific makernotes tags from exif and if thumbnail is there in
exported blob we dont have added the specific makernote parts to be ripped out.
#5 Updated by Richard Levitte about 7 years ago
"I assume that some image viewers have problems as they might take the (then incorrect) thumb for overviews rather
than using the full jpg."
Yup. Among others, the Flickr uploader (on the Flickr web page) shows the low-res thumbnail until it's done uploading the full picture. It's there long enough that one goes "wtf?"...
#8 Updated by Tobias Ellinghaus over 6 years ago
- % Done changed from 20 to 100
- Status changed from Incomplete to Fixed
Great, then it works as intended. Should someone find previews in our exported images in the future we have to deal with them again. Thing is, manufacturers come up with new places to put previews every other week so we have to play tag with them.
#10 Updated by Tom Vijlbrief over 4 years ago
fixes the Pentax DNG issue