[Digikam-users] jpeg compression
arnd.baecker at web.de
Thu Jun 28 15:31:37 BST 2007
On Thu, 28 Jun 2007, [iso-8859-1] Bjørn Kvisli wrote:
> I took an image out of the camera ( a Kodak C40, this time) and saved it with
> different values for jpeg quality. The orginal file was 1.2 MB big, and here
> are the sizes with diffrerent levels of jpeg quality:
> 75 -> 1.3 MB
> 85 -> 1.8 MB
> 90 -> 1.9 MB
> 92 -> 2.3 MB
> 95 -> 2.6 MB
> 97 -> 3.2 MB
> 100 -> 4.5 MB
> All of them bigger than the original file. I don't thimk I understand this.
This suggests, that maybe something like 70 was used inside of the camera?
From the number of pixels Nx * Ny, the number of bytes needed
to store the image (without) compression should follow from
Nx * Ny * (8+8+8), i.e. one Byte per R, G, B.
What is the resolution of your camera?
Anyway, overall the above looks pretty reasonable to me.
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