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JPEG-turbo and arithmetic coding

Posted: 2018-09-10T06:38:44-07:00
by whugemann
I have just installed my first 7.x version of IM (i.e. with magick.exe) as a precompiled windows binary. How do i found out whether it uses jpeg-turbo and if so, how can I use arithmetic coding?

magick -list format
JPEG* JPEG rw- Joint Photographic Experts Group JFIF format (62)

I think that 62 gives a hint on jpeg-turbo (?).

Re: JPEG-turbo and arithmetic coding

Posted: 2018-09-15T07:23:03-07:00
by dlemstra
In the next release you will see that libjpeg-turbo is being used for the Windows binaries. And there was not yet support for creating an image with arithmetic coding so I added that feature for you. You can do this in the next release:

Code: Select all

magick convert logo: -define jpeg:arithmetic-coding=true logo.jpg
And in the output of identify you will see this:

Code: Select all

magick identify -verbose logo.jpg

jpeg:coding: arithmetic