Update th.sh

th.sh

@@ -22,7 +22,7 @@ if [[ $# != 4 ]]; then
     echo "wrong number of arguments
 
 Usage:
-./thumbnails.sh NFRAMES TILE SIZE INPUT
+. th.sh NFRAMES TILE SIZE INPUT
 
 NFRAMES is the number of frames (thumbnails) to generate, e.g., 16;
 TILE is in the form 'MxN' (where M * N should match NFRAMES), e.g., 4x4;
@@ -37,27 +37,28 @@ Example:
 "
     return 1
 fi
-#ffmpeg -start_at_zero -copyts -ss 00:00:14 -i Rammstein\ -\ Radio.mp4 -vf "drawtext=fontfile=/path/to/Arial.ttf:fontsize=45:fontcolor=yellow:box=1:boxcolor=black:x=(W-tw)/2:y=H-th-10:text='%{pts\:gmtime\:0\:%H\\\\\\:%M\\\\\:%S}'" -vframes 1 output.png
 
 NFRAMES=$1
 TILE=$2
 SIZE=$3
 INPUT=$4
-
-#DURATION=$(ffprobe -loglevel error -show_streams "$4" | grep duration= | cut -f2 -d= | head -1)
+#duration in h:m:s for caption
 DURX=$(ffmpeg -i "$4" 2>&1 | grep Duration | awk '{print $2}' | tr -d ,)
+#duraion in seconds for thumnail generatin
 DURATION=$(ffmpeg -i "$4" 2>&1 | grep "Duration"| cut -d ' ' -f 4 | sed s/,// | sed 's@\..*@@g' | awk '{ split($1, A, ":"); split(A[3], B, "."); print 3600*A[1] + 60*A[2] + B[1] }')
+#resolution of video for caption
 RES=$(ffmpeg -i "$4" 2>&1 | grep -oP 'Stream .*, \K[0-9]+x[0-9]+')
+#filesize in Mb for catopn
 FILESIZE=$(du -sm "$4" | awk '{print $1}')
 # generate thumbnails in the /tmp folder
 TMPDIR=/tmp/thumbnails-${RANDOM}/
 mkdir $TMPDIR
-#filame
 
 for (( VARIABLE=0; VARIABLE<NFRAMES; VARIABLE++ ))
 do
+#time at which next snapshot is taken and avoiding blank last snapshot: seconds.xx
 OFFSET=$(echo "scale=2;$VARIABLE*$DURATION/$NFRAMES+$DURATION/$NFRAMES/2" | bc)
-
+#how many zeros we add to temp file thumbnail: bla0009.jpp bla0099.jpg bla0999.jpg
 if [ $VARIABLE -gt 9 ];then
   ZEROS="00"
   if [ $VARIABLE -gt 99 ];then
@@ -69,22 +70,21 @@ if [ $VARIABLE -gt 9 ];then
 else
   ZEROS="000"
 fi
-
-#ffmpeg -start_at_zero -copyts -ss $OFFSET -i "$4" -vf "drawtext=fontfile=/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf:fontsize=45:fontcolor=yellow:box=1:boxcolor=black:x=(W-tw)/2:y=H-th-10:text='%{pts\:gmtime\:0\:%H\\\\\\:%M\\\\\:%S}'" -vframes 1 ${TMPDIR}$ZEROS$VARIABLE.jpg
 ffmpeg -start_at_zero -copyts -ss $OFFSET -i "$4" -vf "drawtext=fontfile=/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf:fontsize=45:fontcolor=white::shadowcolor=black:shadowx=2:shadowy=2:box=1:boxcolor=black@0:x=(W-tw)/40:y=H-th-10:text='%{pts\:gmtime\:0\:%H\\\\\\:%M\\\\\:%S}'" -vframes 1 ${TMPDIR}$ZEROS$VARIABLE.jpg
 done
+#combine thumbnails together
 montage ${TMPDIR}*.jpg -background white -geometry +5+5 -tile $TILE ${TMPDIR}output.jpg
+#put info about video in textfile
 echo $4 >>${TMPDIR}myfile.txt
 echo $RES >>${TMPDIR}myfile.txt
 echo "$FILESIZE Mb" >>${TMPDIR}myfile.txt
 echo $DURX >>${TMPDIR}myfile.txt
-
+#convert textfile in jpg, NB modified policy.xml is needed
 convert -size ${SIZE}x150 -fill black -interline-spacing 10 -background white -pointsize 20 -gravity west caption:@${TMPDIR}myfile.txt ${TMPDIR}text1.jpg
-
-
+#resize combined thumbnails
 convert ${TMPDIR}output.jpg -resize ${SIZE}x${SIZE} ${TMPDIR}th.jpg
+#resize info's width to match combined thumbnails
 thewidth=$(identify -ping -format %w ${TMPDIR}th.jpg)
 convert ${TMPDIR}text1.jpg -crop ${thewidth}x150+0+0 ${TMPDIR}text.jpg
-
-
+#combine info and thumbnails into output file
 montage ${TMPDIR}text.jpg ${TMPDIR}th.jpg -background white -geometry +0+0 -tile 1x2 thumbnails-${RANDOM}.jpg