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Two questions...

Nov 6, 2013, 14:32 (This post was last modified: Nov 6, 2013 16:49 by foxmuldr.)
Post: #16
RE: Two questions...
(Nov 6, 2013 12:01)ofnuts Wrote:  
(Nov 6, 2013 11:04)foxmuldr Wrote:  I have seen your script, but don't know enough about Python to be able to test it, even though I can run it.
You haven't looked very hard because that script is in Perl Smile

Good point. I thought it had the extension .py, But i guess it was .pl. I apologize! :-)

(Nov 6, 2013 12:01)ofnuts Wrote:  
(Nov 6, 2013 11:04)foxmuldr Wrote:  By using C++ and libjpeg I can know for sure what I am dealing with, and therefore verify it to myself.
That wont' make much difference with the script, since you didn't write libjpeg.

GIMP uses libjpeg.

(Nov 6, 2013 12:01)ofnuts Wrote:  
(Nov 6, 2013 11:04)foxmuldr Wrote:  My thoughts are two-fold:
(1) Of interest to learn about JPEG being not lossy after the Nth save.
(2) That it doesn't really matter any longer because of PNG's success, and low file size while maintaining its full losslessness. :-)

PNG is fine for CGI with large area of uniform colors, but it doesn't cut it for photos. My DSLR creates 12PMpx pictures that are around 4.5MB with 98% quality in JPEG format. In PNG they are 33MB (1.5MB in JPEG at 85% quality, still good enough for most display purposes...).

Storage space won't be an issue for much longer. Storage cards are growing and 256GB models are available today (see http://www.amazon.com/Lexar-Professional...gb+microsd $479, and here's a 32GB Micro-SD one http://www.cellphoneshop.net/32san10clas...1327227852 for $42).

That's 7744 pictures at 33MB each in PNG format. Plus, when you zoom way in the compression is seen in JPG photos and wouldn't be there in PNG because of the lossless format. Of course it requires a camera capable of processing that much data into the PNG format.

Personally, I'd rather go lossless than lossy anytime. I'll kick in the extra $80 for my 2TB external hard drive to store all the originals. :-)

-----
UPDATE: I just did a test with this image (5184 x 3456):
http://demo.wpshoppe.com/simplex/files/2...G_9743.jpg

I downloaded to my browser, then copied the image and Ctrl+Shift+V into GIMP, then exported to JPG 98% using all other defaults, and PNG using all defaults. JPG was 7,238 KB, PNG was 21,280 KB, about 3x larger. The difference between the two was striking in color data, not perceptible visually.


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