Hello.
I have seen a quite strange behaviour lately:
If I convert a picture from jpeg to jpeg in a smaller size,
then I end up with 323Kbytes. However, if I do first convert
this same source file to a TIFF (no resize), and then resize
it from tiff to jpeg in the same dimension than the other
file, I end up with only 255Kbytes.
So there seems to be a problem in how the conversion is
handled inside the algorithm.
Visually speaking, I think that both results quality are
exactly the same (watching closely), but the only difference
is that we lose a lot of disk space from jpg to jpg..
Can someone tell me if this is a bug, a lack of optimization
(I think so), or if there is something else to do ?
I would personnally suggest to re-code this part to make
that the file would be uncompressed in memory the same way
than in TIFF, and then compressed again, as the resulting
compression is much better !
Currently I think of doing a script which does the
conversion in two phases, but doing it directly so inside
the algorithm would be great !
Here is the jpg source file I used, in 1600x1200 pixels:
http://w
ww.edenpics.com/pub/bugs/001-001.jpg
This is the resulting file when converted directly from jpg
to a resized jpg using the comand: 'convert -geometry
1024x768 -quality 82 -strip 001-001.jpg 001-001b.jpg:
http://
www.edenpics.com/pub/bugs/001-001b.jpg
Here is the converted file when first converting from jpeg
to TIFF with 'convert 001-001.jpg 001-001tiff.tif'
http
://www.edenpics.com/pub/bugs/001-001tiff.tif
Here is the converted file from this last TIFF to jpeg
resized using the command: 'convert -geometry 1024x768
-quality 82 -strip 001-001tiff.tif 001-001d.jpg'
http://
www.edenpics.com/pub/bugs/001-001d.jpg
I am using ImageMagick V6.0.7.1-14 running on CentOS 4.3.
Please make some tries and tell me what you think.
Thank you,
Daniel
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