#!/bin/bash

# Run this on the command-line to take a source video file
# and output some 1/2-height fields yourself.
#
# Example:
#    bash lacer.txt good.mov  0.5  0.7


VID=${1:?"Usage: bash lacer.txt <video file> <-ss> <-endpos>"}
 SS=${2:?"Usage: bash lacer.txt <video file> <-ss> <-endpos>"}
END=${3:?"Usage: bash lacer.txt <video file> <-ss> <-endpos>"}
CROP="720x240"


echo -n "Removed: "
rm -fv [01]/*pgmyuv  *pgmyuv  *-F[01].png | tr '\n' ' '
echo

for i in 0 1; do
  mkdir -p $i
  # 1st pass, dump even fields as *-F0.png
  # 2nd pass, dump odd  fields as *-F1.png

  mplayer -nosound -ss $SS -endpos $END $VID  -nosound  -vf field=$i  -vo pnm:pgmyuv
  mv *pgmyuv $i/

  # convert the "pgmyuv" format into web viewable PNG format,
  # cropping out the "uv" (chroma) bottom parts so we just
  # see the Y (luminance) part
  for j in $i/*pgmyuv; do
    convert -quality 100 -crop $CROP'+0+0!' $j $(basename $j)-F$i.png
  done
done


# comment out this next line to compare all possible fields to each other...
return



php -- "$@" <<"EOF"
<?
  $pngs = glob('*-F[01].png');
  foreach ($pngs as $i) {
    $scores = [];
    foreach ($pngs as $j) {
      if ($i === $j) continue; // don't compare same field with itself

      // use ImageMagick utility to compare the two fields and output a score
      // (the lower the score, the more similar the fields are)
      $scores[$j] = strtok(
        trim(`env compare -verbose $i $j -metric MAE $i $j null: 2>&1 |fgrep all|cut -f2 -d:`),
        ' '
      );
    }
    asort($scores);
    list($best,$score) = each($scores);
    print_r($scores);
    echo "best $i $best ($score)\n";
  }
}
EOF