Find the most perfect loop part in a movie clip using ImageMagick

Last Updated or created 2024-02-10

Step 1 : Convert movie to png’s

ffmpeg -i mymovie.mp4 %04d.png

Step 2 : Run script in same directory

#!/bin/bash
#set -x
f=MAE
numba=$(ls *png | wc -l)
numbastart=$(( $numba - 10))
numbapadding=$( printf "%04d\n" $numba)
numbapaddingstart=$( printf "%04d\n" $numbastart)
echo "$f "
mkdir -p images/$f
mkdir -p metric/$f
for x in $(seq -w 1 $numbapaddingstart) ; do
	a=$(( $x + 10))
	for y in $(seq -w $a $numbapadding) ; do

	compare -fuzz 20% -verbose -metric $f  $x.png $y.png images/$f/$x-$y.png  2> metric/$f/$x-$y.txt
	echo -n "."

	done
done
echo ""

Step 3 : There are metric stats in a subdirectory, let’s find the most matching parts (top 10)

orgpwd=$PWD
: > /tmp/top10
more metric/MAE/* | grep all   | awk '{ print $2 }' | cut -f1 -d. | sort -n |head | while read ; do
grep -H all metric/MAE/* | cut -f1,2 -d.  | grep " $REPLY" >> /tmp/top10
done
cat /tmp/top10 | cut -f3 -d/ | cut -f1 -d. | while read part ; do
	echo mkdir -p "$part"
	startpart=$(echo $part | cut -f1 -d-)
	endpart=$(echo $part | cut -f2 -d-)
	for file in $(seq -w $startpart $endpart) ; do
		echo cp 0${file}.png $part/
	done
	echo cd "$part" 
	echo ffmpeg -y -framerate 30 -pattern_type glob -i \'*.png\'  -c:v libx264 -pix_fmt yuv420p out.mp4
	echo cd $orgpwd
done

Run above script as ./script.sh > mybash.sh

This generates a bash file, check the contents and run using

“bash mybash.sh”

Last step : There are 10 movies in subdirs which should contain the best looping parts.
check these with: (use CTRL-Q in vlc to stop looping and go to the next file

ls */out.mp4 | while read movie ; do vlc -L $movie ; done

Example loop, made with above

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