[Digikam-devel] [Bug 130525] Saving large (>5M) jpg's result in corrupt file

[Gilles Caulier]

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http://bugs.kde.org/show_bug.cgi?id=130525         




------- Additional Comments From caulier.gilles kdemail net  2007-01-04 16:59 -------
Marcel,

I think than i havethe ultimate solution : using JPEG2000 instead JPEG like preview image format embeded.

If you read the IPTC spec, the preview support JPEG2000 format. Since we have a native  JPEG2000 encoder in digiKam core, we can do it easily. Advantage :

- Better quality.
- Better compression ratio.
- And the most important : we can specify to JPEG2000 codec the target image data size in bytes instead the image quality. The quality settings is automaticly computed by the codec. This way is not possible with JPEG codec. Like this we can limit preview data size to 10Kb for example. We will have 54Kb to store the rest of IPTC data. I think it will always be right.

To decode JPEG2000 preview image with Qt is not a problem. Since KDE 3.3, JPEG2000 decoder (not encoder) is provided by KDE API. Normally, we will change nothing in the preview image loader implementation.

What do you think about ?

Gilles