Shell script to generate tiny still images extracted at 1 second intervals from a video file (requires ffmpeg)

make_tiles.sh

#!/bin/bash
 
# Set things up...
INFILE=$1
if [[ -z "$INFILE" || ! -f $INFILE ]]; then
    echo Please supply the location of a video file
    exit 1
fi
OUTDIR=./tiles
STEP=1
CURR=1
if [ ! -d $OUTDIR ]; then
    mkdir $OUTDIR
fi
 
# Find the duration of the video, in seconds
LEN_TXT=`ffmpeg -i $INFILE 2>&1|grep Duration|cut -f4 -d' '|cut -f1 -d'.'| sed 's/:0/:/g' | sed 's/:/ \\* 3600 + /'|sed 's/:/ \\* 60 + /'`
let "LEN=$LEN_TXT"
echo "Duration=$LEN seconds"

FILENAME=`basename $INFILE`
 
# Make the thumbnail images (32x24 pixels)
while [ $CURR -le $LEN ]
do
    PADDED_NUM=`printf "%05d" $CURR`
    THUMBFILE=$OUTDIR/$FILENAME.$PADDED_NUM.jpg
    echo Processing $CURR of $LEN
    ffmpeg -ss $CURR -i $INFILE -vcodec mjpeg -vframes 1 -y -an -f rawvideo -s 32x24 $THUMBFILE >/dev/null 2>&1
    let CURR+=STEP
done
 
echo Finished.