pic2m2v: implement as a script

The C code was only calling ffmpeg binary anyway...
Additionally create a md5 sum of the input file to avoid
unnecessary conversions.

tools/Makefile.am

@@ -5,5 +5,11 @@ bin_PROGRAMS += spark_fp
 spark_fp_SOURCES = spark_fp.c
 endif
 
-bin_PROGRAMS += pic2m2v
+# no longer use the compiled code...
+noinst_PROGRAMS = pic2m2v
 pic2m2v_SOURCES = pic2m2v.c
+
+# ...use the script instead.
+# hack...
+install-exec-hook:
+	install -D -m 0755 $(srcdir)/pic2m2v.sh $(DESTDIR)$(bindir)/pic2m2v

tools/pic2m2v.sh

@@ -0,0 +1,40 @@
+#!/bin/sh
+#
+# creates still-mpegs from pictures, to be able to display them
+# using a hardware video decoder. Does about the same as pic2m2v.c
+# (C) 2013 Stefan Seyfried
+# License: GPLv2+
+#
+if grep -q TRIPLEDRAGON /proc/cpuinfo; then
+	RES=704x576
+else
+	RES=1280x720
+fi
+
+while true; do
+	IN=$1
+	test -z "$IN" && break
+	shift
+	OUT="/var/cache/`echo ${IN#/}|sed 's@/@.@g'`"
+	MD5=${OUT}.md5
+	M2V=${OUT}.m2v
+	# $MD5 not existing => return code != 0
+	if [ -s $M2V ] && md5sum -c -s $MD5 > /dev/null 2>&1; then
+		echo "$IN is unchanged"
+		touch -r $IN $M2V
+		continue
+	fi
+	if ! [ -e $IN ]; then
+		echo "$IN does not exist!"
+		continue
+	fi
+	echo "converting $IN -> $M2V"
+	ffmpeg -v 31 -y -f mjpeg -i $IN -s $RES $M2V < /dev/null
+	if ! [ -s $M2V ]; then
+		echo "$M2V does not exist - conversion error?"
+		continue
+	fi
+	# set the time identical to input file
+	touch -r $IN $M2V
+	md5sum $IN > $MD5
+done