LOSSLESS JPEG usage

[kkh]

hi
i want to compress lossless jpeg

regarding to : http://www.imagemagick.org/Usage/formats/#jpg_lossless

i used following command:

Code: Select all

convert -quality 100 -compress lossless 1.bmp 1.llj

but i can't see any compression at all, at least the PSNR is lossless.
I am using Linux and windows
(on linux i have already tried libjpeg-6b, libjpeg-7 libjpeg-8)

same results.

where is my mistake?
by the way, i did also try with .jpg extension instead of .llj because i thought libjpeg need that somehow but then the output is lossy.

[fmw42]

I think you need to use JP2000 for lossless jpg, but to do so you need to install if necessary the Jasper delegate library.

convert image.bmp JP2:image.jp2