Testing jpeg compressors & parameters with DSSIM

convert.sh

#!/bin/bash

rm -R im_*
mkdir im_orig im_jpg im_jpg_ss im_jpg_ss_prog im_jpg_moz im_jpg_moz2 
mkdir im_png
mkdir im_webp

i=0
for file in orig/*.jpg; do
    read width height < <(identify -format '%w %h' $file)

    if (( $width / $height >= 2 )); then
        targetSize="6000x800>"
    elif (( $height / $width >= 2 )); then
        targetSize="800x6000>"
    else
        targetSize="800x800>"
    fi

    fileOut=`basename $file`

    convert -resize "$targetSize" -strip $file ./im_png/$fileOut.png &
    convert -resize "$targetSize" -strip -quality 100 $file ./im_orig/$fileOut &
    convert -resize "$targetSize" -strip -quality 90 $file ./im_jpg/$fileOut &
    convert -resize "$targetSize" -strip -quality 90 -sampling-factor "2x2,1x1,1x1" $file ./im_jpg_ss/$fileOut &
    convert -resize "$targetSize" -strip -quality 90 -sampling-factor "2x2,1x1,1x1" -interlace Plane $file ./im_jpg_ss_prog/$fileOut &
    convert -resize "$targetSize" -strip -quality 90 $file -define webp:method=6 -define webp:pass=6 "./im_webp/$fileOut.webp" &
    convert -resize "$targetSize" -strip $file pnm:- | /usr/local/opt/mozjpeg/bin/cjpeg -quality 90 -optimize -progressive > ./im_jpg_moz/$fileOut &
    convert -resize "$targetSize" -strip $file pnm:- | /usr/local/opt/mozjpeg/bin/cjpeg -quality 90,75 -optimize -progressive -sample 2x2 > ./im_jpg_moz2/$fileOut &

    ((i+=1))
    if ! ((i % 4)); then
        echo -n "."
        wait
    fi
done

echo ""

wait
du -h

crop.sh

#!/bin/bash

rm -R $1_cropped
mkdir $1_cropped

i=0
for file in $1/*; do
    fileOut=`basename $file`

    convert -strip -crop +0-20 $file $1_cropped/$fileOut.png &

    ((i+=1))
    if ! ((i % 8)); then
        echo -n "."
        wait
    fi
done
echo ""
wait
du -h

dssim-compare.sh

#!/usr/bin/env bash

# Usage: ./dssim-compare im_webp .webp

function calculate_dissimilarity () {
    # Convert the original JPEG to PNG for DSSIM comparison
    # Also base64 it so we can safely store its result in a variable without needing to write the file to disk

    # Run the JPEG compressor, pipe its output to convert, create a PNG from the newly compressed JPEG and hand it to DSSIM for comparison - all without creating a file on disk to increase runtime performance
    local __current_dissimilarity=$(dssim $1 <(convert "${2}" png:-) | awk '{print $1}')
    echo ${__current_dissimilarity}
}

function is_number () {
#    re='^[0-9]+$'
    re='^[0-9]+([.][0-9]+)?$'
    if [[ $1 =~ $re ]] ; then
        echo 1
    else
        echo 0
    fi
}

i=0
sum_dssim=0
log_filename="dssim_`basename $1`.log"
echo -n "" > $log_filename

for file1 in im_png/*; do
    file2=$1/`basename -s .png $file1`$2
    ((i+=1))
    if ! ((i % 5)); then
        echo -n "."
    fi

    dssim=`calculate_dissimilarity "$file1" "$file2"`
    if [[ `is_number "$dssim"` == 1 ]]; then
        echo "`basename $file2`: $dssim" >> $log_filename
        sum_dssim=`echo "scale=12; $sum_dssim + $dssim" | bc`
    fi
done

wait

echo ""
echo "scale=6; $sum_dssim / $i" | bc

utils.sh

convert -resize 692x820 -strip input1.jpg resized1.png
convert -quality 90 resized1.png resized1_90.jpg
convert -quality 95 resized1.png resized1.webp

convert -resize 692x820 -strip -interlace Plane -quality 90 -sampling-factor "2x2,1x1,1x1" input1.jpg resized1.jpg
identify -format "%f: %Q %b %[jpeg:sampling-factor] %[interlace] %wx%h\n" *

jpegtran -copy none -optimize -progressive resized1_strip_90.jpg -outfile resized1_out.jpg