fast-motion.sh

#!/bin/bash
# Capture a series of images to be used in a time-lapse movie.
# Based on http://demaya.de/wp/2010/08/mit-ffmpeg-zeitraffervideos-erstellen/

# Default settings, parse command line arguments.
sleeptime='1'
defaultduration='30'
stopdate=$(( $(date +%s) + defaultduration ))
capsdir='/tmp/caps'

while (( $# > 0 ))
do
	case $1 in
		-s) sleeptime="$2";                    shift  ;;
		-u) stopdate=$(date -d "$2" +%s);      shift  ;;
		-d) stopdate=$(( $(date +%s) + $2 ));  shift  ;;
		-t) capsdir="$2";                      shift  ;;
		*)
			cat <<EOF
Capture a series of images to be used in a time-lapse movie.

$0 [-s <n>] [-u <date> | -d <n>] [-t <dir>]

	-s <n>
		Sleep <n> seconds after each captured frame. Default is
		$sleeptime second(s).

	-u <date>
		Stop capturing at <date>.
	or

	-d <n>
		Stop capturing after <n> seconds. Default duration is
		$defaultduration second(s).

	-t <dir>
		Save captured images in <dir>. Default is \`$capsdir'.

Examples of usage:
	$0 -s 2 -u '2010-08-10 10:30' -t ~/mycaps
	$0 -s 2 -d 15 -t ~/mycaps
EOF
			exit 1
			;;
	esac
	shift
done

# Prepare and cleanup on exit.
tmpfile="$(mktemp)"
trap 'rm -v "$tmpfile"' 0

mkdir -p "$capsdir" || exit 1

# Capture until we've reached the given time.
while (( $(date +%s) < stopdate ))
do
	filename="$capsdir/pic$(printf %08d $i).jpg"

	ffmpeg -f video4linux2 -s 640x480 -r 1 -i /dev/video0 -vframes 1  \
		-f image2 "$tmpfile"

	convert "$tmpfile"                         \
		-gravity SouthWest                     \
		-box white -draw "text 0,0 '$(date)'"  \
		"$filename" || exit 1

	sleep $sleeptime

	(( i++ ))
done