#!/bin/sh
# takes video as input. makes png screens.

INFILE=$1
NUMSCREENS=$2
CURDIR=`pwd`
TMPDIR=`tempfile`
rm -rf $TMPDIR
mkdir $TMPDIR

# get total vid playback in seconds
totallength=`(echo "get_time_length"; echo "quit") | mplayer -nolirc -slave -quiet -vo null -nosound $INFILE | grep ANS |cut -d'=' -f2 | cut -d'.' -f1`

# substract some
let maxlength=$totallength-10

# calculate interval
let "interval=$maxlength/($NUMSCREENS+1)"

# start screens loopa
cd $TMPDIR
if ! test -e $INFILE; then
 echo please use full paths to the file
 exit 1
fi
screen=0
pos=0
echo -n "Making $NUMSCREENS screens in $maxlength time ($totallength) with $interval seconds in between: "
while test $screen -lt $NUMSCREENS; do
        let screen=$screen+1
        let pos=$pos+$interval
        echo -n "$screen, "
        mplayer -nolirc -quiet -really-quiet -vo png -nosound -frames 5 -ss $pos $INFILE
        if ! test -e 00000005.png; then
                echo error, $pos
                let halfinterval=$interval/2
                let pos=$pos-$halfinterval
                echo error, newpos $pos
                mplayer -nolirc -quiet -really-quiet -vo png -nosound -frames 5 -ss $pos $INFILE
                let pos=$pos+$halfinterval
                echo error, oldpos $pos
        fi
        mv 00000005.png shot`printf "%04d\n" $screen`.png
        rm 0000*png
done
echo "Done."

echo -n "Compressing screens:"

compscreen=0
for i in $TMPDIR/*png; do
        let compscreen=$compscreen+1
        echo -n "$compscreen, "
        pngcrush -q $i $CURDIR/`basename $i`
done

echo " done."
rm -rf $TMPDIR

cd $CURDIR