-define jpeg:fancy-upsampling=off ignored w/ convert
Posted: 2015-03-11T19:11:16-07:00
I believe -define jpeg:fancy-upsampling=off is being ignored with convert but not with mogrify. Given this image and these two commands, I'd expect the same output:
…but the output is different: 1A-1.jpg is 141125 bytes and 1A-1-convert.jpg is 141133 bytes. If I use identify -verbose, they differ in mean, standard deviation, kurtosis, and skewness in the red, green, and blue channels, and overall.
If, however, I do the same commands but leave off -define jpeg:fancy-upsampling=off:
…then the outputs are identical @ 141133 bytes.
This is happening with v6.8.9-8 Q16 on Mac OS X Yosemite.
Code: Select all
mogrify -path ./ -filter Triangle -define filter:support=2.0 -thumbnail 1200 -unsharp 0.25x0.25+8.00+0.065 -dither None -posterize 136 -background Black -alpha Background -quality 82 -define jpeg:fancy-upsampling=off -define png:compression-filter=5 -define png:compression-level=9 -define png:compression-strategy=1 -define png:exclude-chunk=all -interlace none -colorspace sRGB -strip ../assets-unoptimized/1A-1.jpg
Code: Select all
convert ../assets-unoptimized/1A-1.jpg -filter Triangle -define filter:support=2.0 -thumbnail 1200 -unsharp 0.25x0.25+8.00+0.065 -dither None -posterize 136 -background Black -alpha Background -quality 82 -define jpeg:fancy-upsampling=off -define png:compression-filter=5 -define png:compression-level=9 -define png:compression-strategy=1 -define png:exclude-chunk=all -interlace none -colorspace sRGB -strip ./1A-1-convert.jpg
If, however, I do the same commands but leave off -define jpeg:fancy-upsampling=off:
Code: Select all
mogrify -path ./ -filter Triangle -define filter:support=2.0 -thumbnail 1200 -unsharp 0.25x0.25+8.00+0.065 -dither None -posterize 136 -background Black -alpha Background -quality 82 -define png:compression-filter=5 -define png:compression-level=9 -define png:compression-strategy=1 -define png:exclude-chunk=all -interlace none -colorspace sRGB -strip ../assets-unoptimized/1A-1.jpg
Code: Select all
convert ../assets-unoptimized/1A-1.jpg -filter Triangle -define filter:support=2.0 -thumbnail 1200 -unsharp 0.25x0.25+8.00+0.065 -dither None -posterize 136 -background Black -alpha Background -quality 82 -define png:compression-filter=5 -define png:compression-level=9 -define png:compression-strategy=1 -define png:exclude-chunk=all -interlace none -colorspace sRGB -strip ./1A-1-convert.jpg
This is happening with v6.8.9-8 Q16 on Mac OS X Yosemite.
Code: Select all
Version: ImageMagick 6.8.9-8 Q16 x86_64 2015-02-22 http://www.imagemagick.org
Copyright: Copyright (C) 1999-2014 ImageMagick Studio LLC
Features: DPC Modules
Delegates: bzlib freetype jng jpeg lcms lqr ltdl lzma png tiff webp xml zlib