Tas_mania wrote:
I'm a Gimp user who lives in Tasmania and has been getting ideas from Gimpchat for a few years.
Last week I found something I have needed for a long time - A JPEG compression algorithm from Google called
'Guetzli'.
I know you guys are going to appreciate it and use it. I found it can reduce a JPG by about half for publishing to the web.
You will need to get it from GitHub. Search for it there.
I don't work for google (nobody in Tasmania does
) I use Gimp and open source.
I did an article on how I made it work on Ubuntu Linux if anyone needs help.
Do you have some sample files? I downloaded the code from Github and compiled it according to instructions, but the only output I get from it is the message "Invalid input JPEG file". Since that JPEG is straight off my camera, I wonder what is wrong with it.
Btw, Google isn't talking about 50%, but just 30%... from the GitHUb page:
Quote:
Guetzli-generated images are typically 20-30% smaller than images of equivalent quality generated by libjpeg
(and this is a bit ambiguous, since very few people use libjpeg, most Linux distros use a faster fork called libjpeg-turbo).
Edit: it appears that the mistaken "Invalid input JPEG file" this is a
known problem, which is just that guetzli doesn't understand JPEG files with a sub-sampled chroma (which is very frequent in JPEG files, since this is where most of the size gain comes from). Not supporting this right out shows two things:
- the authors have little practical knowledge of JPEG files
- guetzli hasn't been tested with real files from real cameras