I can't tell the difference, and that's a huge size savings. (Which would work better if done from a lossless original source)
(If you can tell the difference, you're free to tweak the quality setting.)
Edit 3:
Another test with lossy source using default settings (would be nice if someone can test with lossless source).
2376M.png.jpg: 43702
2376M.png2.jpg: 17759
Difference: -25943
Edit 4:
Same deal.
2587M.jpg: 43548
2587M2.jpg: 8336
Difference: -35212
2562M.jpg: 39181
2562M2.jpg: 22351
Difference: -16830
2501M.jpg: 44861
2501M2.jpg: 12611
Difference: -32250
2089M.png.jpg: 43029
2089M.png2.jpg: 15128
Difference: -27901
2009M.jpg: 37315
2009M2.jpg: 14375
Difference: -22940
Now, for any of the cases below, left is regular, right is compressed.
100 quality JPG:
(regular is 125749 bytes, compressed is 124178 bytes, 1571 bytes saved)
82 quality JPG:
(regular is 49980 bytes, compressed is 43674 bytes, 6306 bytes saved)
77 quality JPG:
(regular is 44322 bytes, compressed is 38110 bytes, 6212 bytes saved)
The input was always the reference PNG.
The -quality switch lets you trade off compressed file size against
quality of the reconstructed image: the higher the quality setting, the
larger the JPEG file, and the closer the output image will be to the
original input. Normally you want to use the lowest quality setting
(smallest file) that decompresses into something visually indistin-
guishable from the original image. For this purpose the quality set-
ting should be between 50 and 95; the default of 75 is often about
right. If you see defects at -quality 75, then go up 5 or 10 counts at
a time until you are happy with the output image. (The optimal setting
will vary from one image to another.)
-quality 100 will generate a quantization table of all 1’s, minimizing
loss in the quantization step (but there is still information loss in
subsampling, as well as roundoff error). This setting is mainly of
interest for experimental purposes. Quality values above about 95 are
not recommended for normal use; the compressed file size goes up dra-
matically for hardly any gain in output image quality.
Download crushed80.batLanguage: batchcrushedjpeg "%1" output85.jpeg 85
Download crushed75.batLanguage: batchcrushedjpeg "%1" output80.jpeg 80
Download crushed70.batLanguage: batchcrushedjpeg "%1" output75.jpeg
Edit, or a single combined script: Download crushedmany.batLanguage: batchcrushedjpeg "%1" output70.jpeg 70
Language: batchcrushedjpeg "%1" output85.jpeg 85 crushedjpeg "%1" output80.jpeg 80 crushedjpeg "%1" output75.jpeg crushedjpeg "%1" output70.jpeg 70
That says to me "crushedjpeg is not a command, program, or a batch file"...
Does cjpeg have an option to set subsampling to 4:4:4? Without it no matter how I try, the loss is visible against GIMP, even if the file size/quality is greater than GIMP's.
Have we tested this against MozJpeg? https://blog.mozilla.org/research/2014/07/15/mozilla-advances-jpeg-encoding-with-mozjpeg-2-0/
26,904 -> 18,105
31,118 -> 20,537
Language: batch:: Supposed to be ran by itself, no drag'n'dropping :: Hardcoded source name is 0.png, change it if you wish @echo off : start echo Type 0-99 for the desired quality echo Type r to roll by quality step echo Type q to quit set /p quality= if "%quality%"=="q" goto end if "%quality%"=="r" goto bystep goto normal : bystep echo Type the step size set /p step= echo Type 0-99 for where to stop set /p stop= set /a quality=99 : loop crushedjpeg 0.png %quality%.jpeg "%quality%" set /a quality-=%step% if %quality% GTR %stop% goto loop : normal crushedjpeg 0.png %quality%.jpeg "%quality%" goto start : end
F-Zero: 92 / 48,624.
Artifacts at the road stripes are already present on the first sub 50kb jpeg.
Pinball: 76 / 50,578 (woops).
No comments.
Luigi 1: 98 / 40,649.
Artifacts appear around the ligntning if you go under 98, but 98 is already small enough.
Luigi 2: 97 / 42,458.
BG on the right gets blurred and blocked under 97.
Crash: 94 / 47,341.
Hard to see, but artifacts around Crash and on the sky.
So here are the steps that I'd be using when making a publication screenshot for such a game:
Does cjpeg have an option to set subsampling to 4:4:4?
