tif compression issue

[leoutation at gmx.fr]

Hi
I convert many big png files to tif format with Digikam. I noticed tif
compression is not the same when i convert with batch tool and Digikam
editor. Tif compression is set everywhere in my preferences
Example
with digikam batch tool :  55.5 MB png -> 135 MB tif
with digikam editor:         55.5 MB png -> 60.9 MB tif
Compression with editor is better, batch conversion is unusable for me,
files are too big.
I'm wondering which kind tif compression is used in Digikam, LZW,
Deflate ? It could be a good thing to have the choice. 'Deflate' should
be the best. I use it with Gimp, compression is slower but files are smaller
Conditions: Arch Linux system, Digikam git

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Maderios