#!/bin/sh

strip_track()
{

	xmlstarlet ed -d "//mlt/playlist[@id='playlist"$2"']" "$1" > /tmp/out.mlt
	sed -i '/playlist'$2'/d' /tmp/out.mlt
	cp /tmp/out.mlt /tmp/input.mlt

}

INPUT_FILE="$1"
TRACK_TO_KEEP="$2"
MAX_TRACKS="$3"

# copy it for safe keeping.
cp "$1" /tmp/input.mlt

COUNTER=0
for OUTPUT in $(seq $MAX_TRACKS)
do
	if [ ! $COUNTER = $TRACK_TO_KEEP ]
	then
		strip_track /tmp/input.mlt $COUNTER
	fi
	let COUNTER++
done

sed -i 's/playlist'$TRACK_TO_KEEP'/playlist0/g' /tmp/out.mlt

cp /tmp/out.mlt "$1.isolated.mlt"