selective jpeg compression
Posted: 2010-04-08T17:26:11-07:00
Hello,
I am trying to compress a newspaper page containing images and text and have split the image in two layers:
A jpeg layer containing the images and a png layer containing the text.
The png layer is supposed to be displayed over the jpeg so there are parts of the jpeg I do not really care about.
My question is whether I can use imagemagick or any other tool to optimally compress this partially masked image?
Some bytes can be squeezed from the fact that I do not care about the values of some pixels and I need to use that fact in order to reduce size as much as possible.
Actually, I am looking for something similar to the c44 utility (http://djvu.sourceforge.net/doc/man/c44.html -mask option) which allows partially masked images to compress well for djvu wavelet but I need it for jpeg.
Any help will be greatly appreciated...
I am trying to compress a newspaper page containing images and text and have split the image in two layers:
A jpeg layer containing the images and a png layer containing the text.
The png layer is supposed to be displayed over the jpeg so there are parts of the jpeg I do not really care about.
My question is whether I can use imagemagick or any other tool to optimally compress this partially masked image?
Some bytes can be squeezed from the fact that I do not care about the values of some pixels and I need to use that fact in order to reduce size as much as possible.
Actually, I am looking for something similar to the c44 utility (http://djvu.sourceforge.net/doc/man/c44.html -mask option) which allows partially masked images to compress well for djvu wavelet but I need it for jpeg.
Any help will be greatly appreciated...