diff --git a/docker-compose.yml b/docker-compose.yml
index 15f62854bd..c318b6ccb8 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -33,6 +33,7 @@ services:
       - ${LOCAL_HOME}/sipi/config:/sipi/config:delegated
       - ${LOCAL_HOME}/sipi/images:/sipi/images:delegated
       - ${LOCAL_HOME}/sipi/server:/sipi/server:delegated
+      - ${LOCAL_HOME}/sipi/scripts:/sipi/scripts:delegated
     networks:
       - knora-net
     environment:
diff --git a/sipi/scripts/export-moving-image-frames.sh b/sipi/scripts/export-moving-image-frames.sh
index cd339647a7..049747c8c6 100755
--- a/sipi/scripts/export-moving-image-frames.sh
+++ b/sipi/scripts/export-moving-image-frames.sh
@@ -7,78 +7,57 @@
 # - max. 36 frames per matrix
 # - one matrix file corresponds to 6 minutes of film
 
-set -e
-
-dir=$(pwd)
-sep='---------------------------------'
+if [ "${DEBUG:false}" == true ]; then
+  set -ex
+else
+  set -e
+fi
 
-die() {
-	echo >&2 "$@"
-	exit 1
+function printSeparator() {
+  echo "---------------------------------"
 }
 
-usage() {
-	echo "usage: <command> -i [infile]>"
-	echo ${sep}
-	echo "-i = Inpute file"
-	echo ${sep}
+function die() {
+  echo >&2 "$@"
+  exit 1
 }
 
-collect() {
-	film=''
-	cnt=1
-	#for b in `ls`; do
-	for file in *.$1; do
-		[ -f ${file} ]
-		name=$2
-
-		for c in ${cnt}; do
-			if [ "$film" == '' ] || [ "$film" == 'VIDEO_TS.VOB' ]; then
-				film=${file}
-			else
-				case $3 in
-				true) film="$film|$file" ;;
-				esac
-			fi
-		done
-		cnt=$(expr ${cnt} + 1)
-	done
-	needle="|"
-	num=$(grep -o "$needle" <<<"$film" | wc -l)
-	num=$(expr ${num} + 1)
+function usage() {
+  echo "usage: <command> -i [infile]>"
+  printSeparator
+  echo "-i = Inpute file"
+  printSeparator
 }
 
 # default variables
+# current directory
+dir=$(pwd)
+# name of the input file for which the keyframes should be extracted
 infile=''
 
 # alternative to get some information from the source file:
 # ffprobe -v quiet -print_format json -show_format -show_streams ~/sourceFile.mov
 
 while getopts ':i:' OPTION; do
-	case ${OPTION} in
-	i) infile=$OPTARG ;;
-	*) echo 'Unknown Parameter' ;;
-	esac
+  case ${OPTION} in
+  i) infile=$OPTARG ;;
+  *) echo 'Unknown Parameter' ;;
+  esac
 done
 
 if [ $# -eq 0 ]; then
-	usage
-	die ''
+  usage
+  die ''
 fi
 
-# check the arguments: if they exist
-num='^[0-9]+$'
-
-# infile must be given and has to be an mp4
+# infile must be given and has to be an mp4 by checking if mime-type is video/mp4
 if [ -z "${infile}" ]; then
-	# must be given
-	usage
-	die "ERROR: The Input File (-i) is missing"
+  # must be given
+  usage
+  die "ERROR: The Input File (-i) is missing"
 fi
-
-# check if mime-type is video/mp4
-if file -b --mime-type "${infile}" -ne "video/mp4"; then
-	die "ERROR: The Input File (-i) is not mp4"
+if [ "$(file -b --mime-type "${infile}")" != "video/mp4" ]; then
+  die "ERROR: The Input File (-i) is not mp4"
 fi
 
 # get the right output path, the file and the filename (without extension)
@@ -86,19 +65,17 @@ dir=$(dirname "${infile}")
 file=$(basename "${infile}")
 name="${file%.*}"
 
-cd $dir
+cd "${dir}"
 
-# --
 # store the frames and matrix files in specific folder;
 # folder has same unique name as the uploaded file
-mkdir -p $name
-cd $name
+mkdir -p "${name}"
+cd "${name}"
 
-# --
 # read frame rate from input file
-framerate=$(ffprobe -v 0 -of csv=p=0 -select_streams v:0 -show_entries stream=r_frame_rate ../"${file}")
+frame_rate=$(ffprobe -v 0 -of csv=p=0 -select_streams v:0 -show_entries stream=r_frame_rate ../"${file}")
 
-IFS="/" read -a array <<<"$framerate"
+IFS="/" read -ra array <<<"$frame_rate"
 numerator="${array[0]}"
 denumerator="${array[1]}"
 
@@ -110,35 +87,35 @@ aspect=$(ffprobe -v error -select_streams v:0 -show_entries stream=display_aspec
 
 # if aspect ratio does not exist in video file metadata
 if [ ! -z {$aspect} ]; then
-	# get aspect ratio from video dimension (width and height)
-	aspectW=$(ffprobe -v error -select_streams v:0 -show_entries stream=width -of csv=s=x:p=0 ../"${file}")
-	aspectH=$(ffprobe -v error -select_streams v:0 -show_entries stream=height -of csv=s=x:p=0 ../"${file}")
-else 
-	IFS=':' read -a array <<<"$aspect"
-	aspectW="${array[0]}"
-	aspectH="${array[1]}"
+  # get aspect ratio from video dimension (width and height)
+  aspectW=$(ffprobe -v error -select_streams v:0 -show_entries stream=width -of csv=s=x:p=0 ../"${file}")
+  aspectH=$(ffprobe -v error -select_streams v:0 -show_entries stream=height -of csv=s=x:p=0 ../"${file}")
+else
+  IFS=':' read -a array <<<"$aspect"
+  aspectW="${array[0]}"
+  aspectH="${array[1]}"
 fi
 
 # --
-# framesize
+# calculate frame width, height and size
 framewidth='256'
 frameheight=$(($framewidth * $aspectH / $aspectW))
 framesize=${framewidth}'x'${frameheight}
 
-echo ${sep}
+# --
+printSeparator
 echo 'Start with frame export'
 # check the outpath for the frames;
 # if exists, delete it and create new
 if [ -d "frames" ]; then
-	rm -rf ./frames
+  rm -rf ./frames
 fi
 mkdir -p 'frames'
 
-framestart=$(echo ${start} + 1 | bc)
-ffmpeg -i ../${file} -an -ss 1 -f image2 -s ${framesize} -vf framestep=${fps} frames/${name}'_f_%d.jpg' 2>&1
+ffmpeg -i ../"${file}" -an -ss 0 -f image2 -s ${framesize} -vf framestep="${fps}" frames/"${name}"'_f_%d.jpg' 2>&1
 
 echo 'Done'
-echo ${sep}
+printSeparator
 
 # --
 # create the matrix files
@@ -147,15 +124,14 @@ echo 'Start with creating matrix file'
 # change directory frames
 cd frames
 # Get the number of files: one image = one second of movie
-# numfiles is equivalent to the movie duration (in seconds)
-numfiles=(*)
-numfiles=${#numfiles[@]}
+# number_of_frame_files is equivalent to the movie duration (in seconds)
+readonly number_of_frame_files=$(find . -type f | wc -l)
 
 image="${name}_f_1.jpg"
 
 # check if file exists
 if [[ ! -f "${image}" ]]; then
-	die "File not found: ${image}"
+  die "File not found: ${image}"
 fi
 
 # grab the identify string, make sure it succeeded
@@ -179,38 +155,42 @@ frame_height=$(echo "scale=0; ${matrix_height}/6" | bc)
 frame_size="${frame_width}x${frame_height}"
 # get every 10th image; start with the image number 5;
 # how many matrixes will it produce?
-calcmatrix=$(echo "scale=4; (${numfiles}/10)/36" | bc)
+calcmatrix=$(echo "scale=4; (${number_of_frame_files}/10)/36" | bc)
+# Round the exact fraction to the to the next highest integer
+# for the number of matrix files to  create 'nummatrix'
+readonly interim=$(echo "${calcmatrix}+1"|bc)
+readonly nummatrix=${interim%.*}
+
 echo '#Matrix (calculated) '${calcmatrix}
-nummatrix=$(echo ${calcmatrix} | awk '{printf("%.0f\n",$1 + 0.75)}')
 echo '#Matrix (rounded) '${nummatrix}
 
 t=0
 while [ ${t} -lt ${nummatrix} ]; do
-	echo 'Matrix nr '${t}
-	firstframe=$(echo "scale=0; ${t}*360+5" | bc)
-	MATRIX=$(find *_${firstframe}.jpg)' '
-
-	c=1
-	while [ ${c} -lt 36 ]; do
-		sec=$(echo "scale=0; ${firstframe}+(${c}*10)" | bc)
-		if [ $sec -lt $numfiles ]; then
-			img="${name}_f_${sec}.jpg"
-			if [ -f ${img} ]; then
-				MATRIX+=${img}' '
-			fi
-		fi
-
-		let c=c+1
-	done
-
-	# here we make the montage of every matrix file
-	# montage -size 320x180 DB_4_5.jpg DB_4_15.jpg DB_4_25.jpg DB_4_35.jpg -geometry +0+0 montage1.jpg
-	# $(echo "montage -size ${matrix_size} ${MATRIX} -tile 6x6 -geometry +0+0 -resize ${frame_size} ../matrix/${name}'_m_'${t}'.jpg'")
-	montage -size ${matrix_size} ${MATRIX} -tile 6x6 -geometry +0+0 -resize ${frame_size} ../${name}'_m_'${t}'.jpg' 2>&1
-
-	let t=t+1
+  echo 'Matrix nr '${t}
+  firstframe=$(echo "scale=0; ${t}*360+1" | bc)
+  MATRIX=$(find *_${firstframe}.jpg)' '
+
+  c=1
+  while [ ${c} -lt 36 ]; do
+    sec=$(echo "scale=0; ${firstframe}+(${c}*10)" | bc)
+    if [ $sec -lt $number_of_frame_files ]; then
+      img="${name}_f_${sec}.jpg"
+      if [ -f ${img} ]; then
+        MATRIX+=${img}' '
+      fi
+    fi
+
+    let c=c+1
+  done
+
+  # here we make the montage of every matrix file
+  # montage -size 320x180 DB_4_5.jpg DB_4_15.jpg DB_4_25.jpg DB_4_35.jpg -geometry +0+0 montage1.jpg
+  # $(echo "montage -size ${matrix_size} ${MATRIX} -tile 6x6 -geometry +0+0 -resize ${frame_size} ../matrix/${name}'_m_'${t}'.jpg'")
+  montage -size ${matrix_size} ${MATRIX} -tile 6x6 -geometry +0+0 -resize ${frame_size} ../${name}'_m_'${t}'.jpg' 2>&1
+
+  let t=t+1
 
 done
 
 echo 'Done'
-echo ${sep}
+printSeparator